REFERENCES.
[ [1] Cloetta: Dixon Mann’s Forensic Medicine and Toxicology, p. 463.
[ [2] Oliver, Sir T.: Diseases of Occupation, p. 142.
[ [3] Goadby, K. W.: Departmental Committee on Lead Poisoning, etc., in China and Earthenware Manufacture, Appendix No. XXV.
[ [4] Meillère and Richer: Meillère’s Le Saturnisme. Paris, 1903.
[ [5] Blyth: Abstract of Proc. Chem. Soc., 1887-88.
[ [6] Hougounencq: Meillère’s Le Saturnisme, p. 73.
[ [7] Dixon Mann: British Medical Journal, 1893.
[ [8] Gautier: Société de Biologie, April, 1903.
[ [9] Oliver, Sir T.: British Medical Journal, May 13, 1911, p. 1096.
[10] Glibert, D. J.: Le Saturnisme Expérimental. Extrait des Rapports Annuels de l’Inspection du Travail. Bruxelles, 1906.
[11] Oliver, Sir T.: Diseases of Occupation, p. 139.
[12] Chyzer, A.: Des Intoxications par le Plomb se présentant dans la Céramique en Hongrie. Budapest, 1908.
[13] Garrod: The Lancet, 1870.
[14] Goadby, K. W.: Departmental Committee on Lead Poisoning, etc., in China and Earthenware Manufacture, Appendix XXV.
[15] Hunter, William: Severest Anæmias.
[16] Goadby, K. W.: The Lancet, March 11, 1911.
CHAPTER IV
STATISTICS OF PLUMBISM[A]
[A] Based mainly on reports received from certifying factory surgeons during the ten years 1900-1909.
Classification of notified cases of lead poisoning was carried out on practically the same lines between the years 1900 and 1909, and comparison of the data so collected has interest, in view of their large number—nearly 7,000—in respect of (1) increase or decrease in recorded amount in each one of eighteen classes of industries; (2) severity and number of attack—i.e., whether first, second, third, or chronic; and (3) main symptoms.
Notification was first enjoined by Section 29 of the Factory and Workshop Act, 1895, which subsequently, on consolidation of the Factory Acts, became Section 73 of the Act of 1901. This enactment requires every medical practitioner, attending on, or called in to visit, a patient whom he believes to be suffering from lead poisoning contracted in a factory or workshop, to notify the case forthwith to the Chief Inspector of Factories at the Home Office; and a similar obligation is imposed on the occupier of a factory or workshop to send written notice of every such case to the certifying surgeon and inspector of factories for the district. In form there is close similarity between this section and that requiring notification under the Infectious Diseases (Notification) Act; but whereas the symptoms of these diseases are, within well-recognized limits, precise, in lead poisoning the differential diagnosis has not infrequently to be made from a variety of common ailments—headache, anæmia, rheumatism, abdominal pain; and there is no precise standard of what constitutes lead poisoning.
The notification of the practitioner as a rule gives no information beyond the belief that the case is one of lead poisoning. As a matter of routine the notification is followed up by an inquiry by the certifying surgeon and inspector to see whether regulations already in force have been infringed in the particular work-place or not, and as to how far there may have been contributory negligence on the part of the sufferer. The data supplied on the surgeon’s report form the basis of the tabulation[1]. Brief explanation is wanted of the method adopted in classification. Cases represent all attacks reported within a year, and not previously reported within the preceding twelve months, so as to make the number of persons and cases in a year the same. Where the interval between two reports on the same person was more than twelve months, the fresh attack was again included. The number of such second reports on persons already included in a return numbered 284 (4·2 per cent.), and a portion of these certainly, probably not more than 100, have been included twice or thrice in the total 6,638 cases. Cases in which there was obvious error in diagnosis, or in which the opinion of the certifying surgeon was very strongly against the diagnosis (especially when the report had been made in the first instance by the occupier alone, and not by a medical practitioner), were excluded from the return. These numbered 458 (6·8 per cent.). Others, again, where there was a strong element of doubt, but not to be regarded as more than a difference of opinion between two medical men, were marked doubtful and included. Of these there were 424 (6·3 per cent.).
The classification of industries was designed to represent the way in which the poisoning may be supposed to originate from (a) lead fumes (1 to 4), (b) handling metallic lead (5 and 6), (c) dust from lead compounds (7 to 14), and (d) lead paint (15 to 17). We attach now only slight importance to this attempt to define causation, as it will appear from our survey that we regard almost all cases as the result of inhalation either of fumes or dust.
The reports describe not only the particular attack, but also the general condition of the patient at the time of the attack. Very frequently a combination of symptoms—colic, anæmia, and varying degree of paralysis—are described as present, and when this is the case each one of them has been entered under the appropriate heading. The total number of symptoms, therefore, greatly exceeds the number of cases, but this does not affect the correctness of the estimate of each one as a proportion on the total number reported. The reports do not give detailed information such as can be gained from hospital records. Especially is this the case with the symptoms of paralysis and encephalopathy.
[Table III.] shows the number of reported cases included in returns for each of the years 1900 to 1909. On the total figures there has been a reduction of 47·7 per cent. In the several industries the salient feature is that the considerable diminution achieved is limited to industries—notably white lead, earthenware and china, litho-transfers, and paints and colours—in which, under regulations or special rules, locally applied exhaust ventilation for the removal of dust, and periodical medical examination of the workers, have been required. Where, owing to the nature of the processes carried on, it has been found impracticable, in the present state of knowledge, to apply local exhaust ventilation, and where periodical examination of the workers is lacking, as in smelting of metals[A] and industries using paint, there has been tendency to increase in the number of cases. In coach-building the increase is in part due to activity in the motor-car industry.
[A] This is now required by the regulations dated August 12, 1911.
TABLE III.—NOTIFICATION OF POISONING BY LEAD (under S. 73, 1901), 1900-1909.
| Industry. | Reported Cases. | |||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total 1900-09. | 1909. | 1908. | 1907. | 1906. | 1905. | 1904. | 1903. | 1902. | 1901. | 1900. | ||||||||||||||
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) | (11) | (12) | |||||||||||||
| Lead poisoning | 6,762 | 275 | 553 | 30 | 646 | 32 | 578 | 26 | 632 | 33 | 592 | 23 | 597 | 26 | 614 | 19 | 629 | 14 | 863 | 34 | 1,058 | 38 | ||
| 1 | . | Smelting of metals | 412 | 18 | 66 | 5 | 70 | 2 | 28 | 2 | 38 | 1 | 24 | 1 | 33 | 1 | 37 | 2 | 28 | 54 | 3 | 34 | 1 | |
| 2 | . | Brass works | 75 | 4 | 5 | 6 | 9 | 1 | 11 | 5 | 1 | 10 | 1 | 15 | 5 | 6 | 1 | 3 | ||||||
| 3 | . | Sheet lead and lead piping | 109 | 3 | 9 | 2 | 14 | 6 | 7 | 9 | 7 | 11 | 12 | 17 | 17 | 1 | ||||||||
| 4 | . | Plumbing and soldering | 217 | 12 | 28 | 27 | 20 | 2 | 16 | 4 | 24 | 2 | 21 | 3 | 26 | 23 | 1 | 23 | 9 | |||||
| 5 | . | Printing | 200 | 17 | 21 | 1 | 30 | 2 | 26 | 3 | 16 | 2 | 19 | 4 | 15 | 13 | 2 | 19 | 23 | 1 | 18 | 2 | ||
| 6 | . | File-cutting | 211 | 19 | 8 | 9 | 2 | 10 | 15 | 12 | 20 | 4 | 24 | 2 | 27 | 1 | 46 | 7 | 40 | 3 | ||||
| 7 | . | Tinning and enamelling | 138 | 2 | 21 | 10 | 25 | 18 | 1 | 14 | 1 | 10 | 14 | 11 | 10 | 5 | ||||||||
| 8 | . | White lead | 1,295 | 31 | 32 | 2 | 79 | 3 | 71 | 108 | 7 | 90 | 1 | 116 | 2 | 109 | 2 | 143 | 1 | 189 | 7 | 358 | 6 | |
| 9 | . | Red lead | 108 | 10 | 12 | 7 | 6 | 10 | 11 | 6 | 13 | 14 | 19 | |||||||||||
| 10 | . | China and earthenware | 1,065 | 57 | 58 | 5 | 117 | 12 | 103 | 8 | 107 | 4 | 84 | 3 | 106 | 4 | 97 | 3 | 87 | 4 | 106 | 5 | 200 | 8 |
| 10 | a. | Litho-transfers | 48 | 1 | 2 | 10 | 5 | 5 | 3 | 3 | 2 | 7 | 10 | |||||||||||
| 11 | . | Glass cutting and polishing | 48 | 9 | 4 | 2 | 3 | 1 | 4 | 4 | 1 | 3 | — | 4 | 8 | 2 | 11 | 3 | 7 | |||||
| 12 | . | Enamelling iron plates | 52 | 1 | 3 | 7 | 6 | 4 | 2 | 3 | 4 | 3 | 1 | 9 | 11 | |||||||||
| 13 | . | Electric accumulators | 285 | 6 | 27 | 2 | 25 | 1 | 21 | 26 | 27 | 1 | 33 | 28 | 16 | 1 | 49 | 1 | 33 | |||||
| 14 | . | Paints and colours | 422 | 7 | 39 | 2 | 25 | 35 | 1 | 37 | 57 | 1 | 32 | 1 | 39 | 1 | 46 | 56 | 56 | 1 | ||||
| 15 | . | Coach-building | 697 | 41 | 95 | 6 | 70 | 3 | 70 | 3 | 85 | 7 | 56 | 3 | 49 | 4 | 74 | 5 | 63 | 1 | 65 | 4 | 70 | 5 |
| 16 | . | Ship-building | 269 | 10 | 27 | 1 | 15 | 22 | 1 | 26 | 1 | 32 | 2 | 48 | 24 | 1 | 15 | 1 | 28 | 1 | 32 | 2 | ||
| 17 | . | Paint used in other industries | 452 | 18 | 42 | 47 | 1 | 49 | 2 | 37 | 3 | 49 | 2 | 27 | 3 | 46 | 1 | 44 | 1 | 61 | 50 | 5 | ||
| 18 | . | Other industries | 659 | 20 | 57 | 2 | 78 | 5 | 56 | 2 | 66 | 2 | 70 | 1 | 53 | 3 | 40 | 64 | 89 | 1 | 86 | 4 | ||
The principal figures are those of the cases, fatal and non-fatal; the small figures relate to fatal cases only.
For the sake of completeness the figures for the years 1910 and 1911 are given below. The grand totals are comparable with those for each of the years 1900 to 1909, but not the total for all of the several groups of industries. Thus, the name of heading No. 7 is altered to “Tinning of metals,” and No. 12 to “Vitreous enamelling,” because of regulations widening their scope, and now including cases which previously figured in No. 18, “Other industries.”
| Industry. | 1911. | 1910. | ||
|---|---|---|---|---|
| Lead poisoning | 669 | 37 | 505 | 38 |
| Smelting of metals | 48 | 3 | 34 | 5 |
| Brass works | 9 | 1 | 7 | |
| Sheet lead and lead piping | 12 | 4 | ||
| Plumbing and soldering | 37 | 2 | 25 | 1 |
| Printing | 32 | 2 | 33 | 4 |
| File-cutting | 18 | 2 | 9 | 1 |
| Tinning of metals | 13 | 17 | ||
| Vitreous enamelling | 19 | 1 | 17 | |
| White lead | 41 | 2 | 34 | 1 |
| Red lead | 13 | 1 | 10 | |
| China and earthenware | 92 | 6 | 77 | 11 |
| Litho-transfers | 1 | 1 | ||
| Glass cutting and polishing | 5 | — | ||
| Electric accumulators | 24 | 1 | 31 | |
| Paints and colours | 21 | 17 | 1 | |
| Coach and car painting | 104 | 5 | 70 | 6 |
| Ship-building | 36 | 6 | 21 | 2 |
| Use of paint in other industries | 56 | 1 | 51 | 3 |
| Other industries | 88 | 4 | 47 | 3 |
TABLE IV.—ANALYSIS OF REPORTS ON LEAD POISONING BY CERTIFYING SURGEONS FROM JANUARY 1, 1900, TO DECEMBER 31, 1909.
| No. | Occupation. | Total. | Severity of Symptoms. | Number of Attack. | Main Symptoms. | |||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Severe. | Moderate. | Slight. | First. | Second. | Third, or Chronic. | Gastric. | Anæmia. | Headache. | Paretic. | Encephalo- pathic. | Rheumatic. | Other. | ||||||||||||||||||
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) | (11) | (12) | (13) | (14) | (15) | (16) | |||||||||||||||
| M. | F. | M. | F. | M. | F. | M. | F. | M. | F. | M. | F. | M. | F. | M. | F. | M. | F. | M. | F. | M. | F. | M. | F. | M. | F. | M. | F. | |||
| 1 | Smelting of metals: | |||||||||||||||||||||||||||||
| Cases | 411 | — | 104 | — | 105 | — | 197 | — | 276 | — | 65 | — | 64 | — | 325 | — | 99 | — | 18 | — | 99 | — | 9 | — | 66 | — | 11 | — | ||
| Per cent. | 100 | — | 25·3 | — | 25·6 | — | 47·9 | — | 67·2 | — | 16·8 | — | 15·6 | — | 79·1 | — | 24·1 | — | 4·4 | — | 24·1 | — | 2·2 | — | 16·1 | — | 2·7 | — | ||
| 2 | Brass works: | |||||||||||||||||||||||||||||
| Cases | 70 | 4 | 26 | 2 | 20 | 1 | 22 | 1 | 40 | 3 | 11 | 1 | 17 | — | 57 | 4 | 28 | 3 | 16 | 3 | 28 | 2 | — | — | 9 | 1 | 3 | — | ||
| Per cent. | 100 | — | 37·1 | — | 28·6 | — | 31·5 | — | 57·1 | — | 15·7 | — | 24·3 | — | 81·4 | — | 40·0 | — | 22·9 | — | 40·0 | — | — | — | 12·9 | — | 4·3 | — | ||
| 3 | Sheet lead and lead piping: | |||||||||||||||||||||||||||||
| Cases | 102 | 4 | 25 | 1 | 29 | 1 | 47 | 2 | 72 | 3 | 17 | — | 11 | 1 | 82 | 2 | 28 | 1 | 9 | 1 | 26 | 2 | 2 | — | 11 | 1 | 1 | 1 | ||
| Per cent. | 100 | — | 24·5 | — | 28·4 | — | 46·1 | — | 70·6 | — | 16·7 | — | 10·8 | — | 80·4 | — | 27·5 | — | 8·8 | — | 25·5 | — | 2·0 | — | 10·8 | — | 1·0 | — | ||
| 4 | Plumbing and soldering: | |||||||||||||||||||||||||||||
| Cases | 186 | 30 | 65 | 6 | 49 | 6 | 65 | 16 | 114 | 22 | 30 | 1 | 32 | 3 | 146 | 25 | 58 | 14 | 23 | 10 | 46 | 7 | 10 | — | 21 | 4 | 8 | — | ||
| Per cent. | 100 | 100 | 34·9 | 20·0 | 26·3 | 20·0 | 34·9 | 53·3 | 61·3 | 73·3 | 16·1 | 3·3 | 17·2 | 10·0 | 78·5 | 83·3 | 31·2 | 46·7 | 12·4 | 33·3 | 24·7 | 23·3 | 5·4 | — | 11·3 | 13·3 | 4·3 | — | ||
| 5 | Printing: | |||||||||||||||||||||||||||||
| Cases | 190 | 6 | 55 | — | 43 | 1 | 82 | 5 | 118 | 6 | 29 | — | 33 | — | 144 | 6 | 41 | 3 | 22 | 1 | 36 | — | 8 | — | 18 | — | 8 | — | ||
| Per cent. | 100 | — | 28·9 | — | 22·6 | — | 43·2 | — | 62·1 | — | 15·3 | — | 17·4 | — | 75·8 | — | 21·6 | — | 11·6 | — | 18·9 | — | 4·2 | — | 9·5 | — | 4·2 | — | ||
| 6 | File-cutting: | |||||||||||||||||||||||||||||
| Cases | 174 | 34 | 85 | 8 | 34 | 5 | 48 | 21 | 49 | 24 | 39 | 4 | 78 | 6 | 104 | 23 | 50 | 17 | 15 | 2 | 80 | 3 | 7 | — | 16 | — | 20 | 3 | ||
| Per cent. | 100 | 100 | 48·9 | 23·5 | 19·5 | 14·7 | 27·6 | 61·8 | 28·2 | 70·6 | 22·4 | 11·8 | 44·8 | 17·6 | 59·8 | 67·7 | 28·7 | 50·0 | 8·6 | 5·9 | 46·0 | 8·8 | 4·0 | — | 9·2 | — | 11·5 | 8·8 | ||
| 7 | Tinning and enamelling of hollow-ware: | |||||||||||||||||||||||||||||
| Cases | 84 | 53 | 26 | 13 | 27 | 16 | 31 | 24 | 50 | 31 | 18 | 16 | 15 | 6 | 65 | 49 | 33 | 12 | 9 | 3 | 19 | 13 | 4 | 2 | 8 | 4 | 1 | — | ||
| Per cent. | 100 | 100 | 31·0 | 24·5 | 32·1 | 30·2 | 36·9 | 45·3 | 59·5 | 58·5 | 21·4 | 30·2 | 17·9 | 11·3 | 77·4 | 92·5 | 39·3 | 22·6 | 10·7 | 5·7 | 22·6 | 24·5 | 4·8 | 3·8 | 9·5 | 7·5 | 1·2 | — | ||
| 8 | White lead: | |||||||||||||||||||||||||||||
| Cases | 1,167 | 76 | 317 | 27 | 235 | 11 | 593 | 33 | 961 | 56 | 108 | 9 | 49 | 3 | 1,003 | 59 | 286 | 8 | 51 | 5 | 120 | 7 | 59 | 6 | 98 | 7 | 14 | 2 | ||
| Per cent. | 100 | 100 | 27·2 | 35·5 | 20·1 | 14·5 | 50·8 | 43·4 | 82·4 | 73·7 | 9·3 | 11·8 | 4·2 | 3·9 | 85·9 | 77·6 | 2·5 | 10·5 | 4·4 | 6·6 | 10·3 | 9·2 | 5·1 | 7·9 | 8·4 | 9·2 | 1·2 | 2·6 | ||
| 9 | Red lead: | |||||||||||||||||||||||||||||
| Cases | 108 | — | 30 | — | 31 | — | 45 | — | 90 | — | 8 | — | 8 | — | 87 | — | 28 | — | 8 | — | 14 | — | 9 | — | 13 | — | 3 | — | ||
| Per cent. | 100 | — | 27·8 | — | 28·7 | — | 41·7 | — | 83·3 | — | 7·4 | — | 7·4 | — | 80·6 | — | 25·9 | — | 7·4 | — | 13·0 | — | 8·3 | — | 12·0 | — | 2·8 | — | ||
| 10 | China and earthenware: | |||||||||||||||||||||||||||||
| Cases | 490 | 572 | 102 | 86 | 158 | 181 | 216 | 286 | 297 | 469 | 91 | 65 | 87 | 17 | 318 | 430 | 93 | 183 | 78 | 181 | 147 | 79 | 26 | 43 | 52 | 67 | 39 | 8 | ||
| Per cent. | 100 | 100 | 20·8 | 15·0 | 32·2 | 31·6 | 44·1 | 50·0 | 60·6 | 82·0 | 18·6 | 11·4 | 17·7 | 3·0 | 64·9 | 75·2 | 19·0 | 32·0 | 15·9 | 31·6 | 30·0 | 13·8 | 5·3 | 7·5 | 10·6 | 11·7 | 8·0 | 1·4 | ||
| 10 | a | Litho-transferers: | ||||||||||||||||||||||||||||
| Cases | 20 | 28 | 2 | 5 | 2 | 8 | 15 | 15 | 17 | 27 | 2 | — | — | 1 | 16 | 25 | 2 | 8 | 6 | 14 | 1 | 8 | — | 2 | 5 | 2 | — | 1 | ||
| Per cent. | 100 | 100 | 10·0 | 17·9 | 10·0 | 28·6 | 75·0 | 53·6 | 85·0 | 96·4 | 10·0 | — | — | 3·6 | 80·0 | 89·3 | 10·0 | 28·6 | 30·0 | 50·0 | 5·0 | 28·6 | — | 7·1 | 25·0 | 7·1 | — | 3·6 | ||
| 11 | Glass cutting and polishing: | |||||||||||||||||||||||||||||
| Cases | 47 | — | 20 | — | 11 | — | 16 | — | 21 | — | 9 | — | 17 | — | 28 | — | 9 | — | 2 | — | 14 | — | 2 | — | 4 | — | 9 | — | ||
| Per cent. | 100 | — | 42·5 | — | 23·4 | — | 34·0 | — | 44·7 | — | 19·1 | — | 36·2 | — | 59·6 | — | 19·1 | — | 4·2 | — | 29·8 | — | 4·2 | — | 8·5 | — | 19·1 | — | ||
| 12 | Enamelling of iron plates: | |||||||||||||||||||||||||||||
| Cases | 38 | 14 | 6 | 6 | 19 | 4 | 13 | 3 | 31 | 11 | 7 | 2 | — | — | 37 | 8 | 3 | 5 | 2 | 2 | 3 | 3 | — | 1 | 6 | 1 | — | — | ||
| Per cent. | 100 | 100 | 15·8 | 42·9 | 50·0 | 28·6 | 34·2 | 21·4 | 81·6 | 78·6 | 18·4 | 14·3 | — | — | 97·4 | 57·1 | 7·9 | 35·7 | 5·3 | 14·3 | 7·9 | 21·4 | — | 7·1 | 15·8 | 7·1 | — | — | ||
| 13 | Electric accumulators: | |||||||||||||||||||||||||||||
| Cases | 281 | — | 58 | — | 70 | — | 151 | — | 222 | — | 40 | — | 13 | — | 255 | — | 70 | — | 10 | — | 34 | — | 5 | — | 12 | — | 2 | — | ||
| Per cent. | 100 | — | 20·6 | — | 24·9 | — | 53·7 | — | 79·0 | — | 14·2 | — | 4·6 | — | 90·8 | — | 24·9 | — | 3·6 | — | 12·1 | — | 1·8 | — | 4·3 | — | 0·7 | — | ||
| 14 | Paint and colour works: | |||||||||||||||||||||||||||||
| Cases | 397 | 21 | 111 | 2 | 104 | 4 | 176 | 15 | 290 | 16 | 61 | 3 | 39 | 2 | 344 | 19 | 121 | 8 | 36 | 2 | 81 | 1 | 8 | 1 | 43 | 2 | 7 | — | ||
| Per cent. | 100 | 100 | 27·9 | 9·5 | 26·2 | 19·0 | 44·4 | 71·5 | 73·1 | 76·2 | 15·4 | 14·3 | 9·8 | 9·5 | 86·7 | 90·5 | 30·5 | 38·1 | 9·1 | 9·5 | 20·4 | 4·8 | 2·0 | 4·8 | 10·8 | 9·5 | 1·8 | — | ||
| 15 | Coach-making: | |||||||||||||||||||||||||||||
| Cases | 678 | 3 | 176 | — | 187 | 2 | 293 | 1 | 405 | 2 | 127 | — | 114 | 1 | 537 | 2 | 178 | — | 109 | — | 157 | 1 | 16 | — | 79 | — | 23 | — | ||
| Per cent. | 100 | — | 26·0 | — | 27·6 | — | 43·2 | — | 59·8 | — | 18·7 | — | 16·8 | — | 79·2 | — | 26·3 | — | 16·1 | — | 23·2 | — | 2·4 | — | 11·7 | — | 3·4 | — | ||
| 16 | Ship-building: | |||||||||||||||||||||||||||||
| Cases | 261 | — | 93 | — | 51 | — | 108 | — | 181 | — | 41 | — | 24 | — | 207 | — | 77 | — | 27 | — | 54 | — | 8 | — | 23 | — | 4 | — | ||
| Per cent. | 100 | — | 35·6 | — | 19·5 | — | 41·4 | — | 69·0 | — | 15·7 | — | 9·2 | — | 79·3 | — | 29·5 | — | 10·3 | — | 20·7 | — | 3·1 | — | 8·8 | — | 1·5 | — | ||
| 17 | Paints used in other industries: | |||||||||||||||||||||||||||||
| Cases | 405 | 42 | 127 | 11 | 97 | 7 | 174 | 22 | 238 | 36 | 83 | 4 | 71 | 1 | 329 | 36 | 108 | 21 | 40 | 13 | 110 | 12 | 10 | 1 | 41 | 3 | 8 | 1 | ||
| Per cent. | 100 | 100 | 31·4 | 26·2 | 23·9 | 16·7 | 43·0 | 52·4 | 58·8 | 85·7 | 20·5 | 9·5 | 17·5 | 2·4 | 81·2 | 85·7 | 26·7 | 50·0 | 9·9 | 31·0 | 27·2 | 28·6 | 2·5 | 2·4 | 10·1 | 7·1 | 2·0 | 2·4 | ||
| 18 | Other industries: | |||||||||||||||||||||||||||||
| Cases | 528 | 114 | 160 | 37 | 117 | 22 | 230 | 52 | 329 | 93 | 85 | 14 | 86 | 5 | 428 | 91 | 161 | 42 | 58 | 18 | 121 | 15 | 17 | 6 | 43 | 15 | 15 | — | ||
| Per cent. | 100 | 100 | 30·3 | 32·5 | 22·2 | 19·3 | 43·6 | 45·6 | 62·3 | 81·6 | 16·1 | 12·3 | 16·3 | 4·4 | 81·1 | 79·8 | 30·5 | 36·8 | 11·0 | 15·8 | 22·9 | 13·2 | 3·2 | 5·3 | 8·1 | 13·2 | 2·8 | — | ||
| Total cases | 5,637 | 1,001 | 1,588 | 204 | 1,389 | 269 | 2,522 | 496 | 3,800 | 799 | 871 | 119 | 758 | 46 | 4,512 | 779 | 1,473 | 325 | 539 | 255 | 1,190 | 153 | 200 | 62 | 568 | 107 | 176 | 16 | ||
| „ per cent. | 100 | 100 | 28·2 | 20·4 | 24·7 | 26·9 | 44·7 | 49·5 | 67·4 | 79·8 | 15·5 | 11·9 | 13·4 | 4·6 | 80·0 | 77·8 | 26·1 | 32·5 | 9·6 | 25·5 | 21·1 | 15·3 | 3·5 | 6·2 | 10·3 | 10·7 | 3·1 | 1·6 | ||
To reduce the size of the table, columns showing the number in each occupation in which (a) the severity of attack, and (b) the number of attack were not stated, have been omitted. Of the former there were 170, and of the latter 245. The total figures, however, in Column 3 include them.
[Table IV.] shows the severity of the attacks as stated by the surgeon, the number of attack, and the main symptoms. The personal element enters into the character of the reports, and symptoms which one surgeon might describe as slight another might regard as moderate, or even severe. In general, however, “slight” includes cases of (1) colic without complication, and of comparatively short duration; (2) anæmia in adolescence aggravated by employment; and (3) either of the above with tendency to weakness of the extensors. “Moderate” includes (1) a combination of colic with anæmia; (2) profound anæmia; (3) partial paralysis; and (4) cases in which there is constitutional debility. “Severe” includes (1) marked paralysis; (2) encephalopathic conditions—convulsions, optic neuritis, and mental affections; (3) grave undermining of the constitution associated with paralysis, renal disease, and arterio-sclerosis. The reports are made during the attack, and information is not received of the sequelæ which may supervene, except in the event of a later report as the result of fresh exposure to lead. Number of attack has reference to definite occurrence of disability. Transient attacks which have preceded the disabling condition have been usually disregarded. It was necessary to limit the number of attacks which might be regarded as indicating chronic plumbism, and all those included in Column 10 are either third attacks or cases of chronic lead poisoning. Among the main symptoms, the headings “Gastric,” “Paretic,” “Encephalopathic,” and “Rheumatic or Arthralgic,” represent fairly accurately the relative incidence of these in cases of lead poisoning in this country; those under the headings “Anæmia” and “Headache” are useful in comparing relative incidence on the two sexes, but they occur, probably, much more frequently than the figures would indicate; those under “Tremor” and “Other” are less valuable. Under “Other” are included “Gout,” “Nephritis,” or “Cerebral Hæmorrhage,” so that entry under this head indicates chronic, rather than mild, lead poisoning. The conclusions from the table are easy to draw, as, in general, the feature which causes severity of symptoms to be prominent leaves its mark also on “Number of Attack” and “Main Symptoms.” Thus, in the industries in which severe cases exceed the average (brass, plumbing, printing, file-cutting, tinning, glass-cutting, ship-building, paints used in other industries, and other industries), the chronic nature of the plumbism is markedly above the average, and some severe symptom, usually paralysis, is also above the average. An exception to this rule is china and earthenware, where severity is considerably below the average, but where, among men, the figures for chronic lead poisoning and paralysis are distinctly high. It will be seen, however, that the proportion of slight cases even in this industry is below the average. On the other hand, severity is below the average in smelting, white lead, red lead, litho-transfers, enamelling, electric accumulators, paints and colours, and coach-painting, and the symptoms in these industries are, in general, colic rather than high degree of paralysis; but in them a severe symptom which is above the average, in general, is encephalopathy. The explanation of these differences depends, we believe, on two factors: (1) Duration of employment, with which, naturally, the age of the worker is associated; (2) opportunity of inhaling lead dust. The longer the employment, the more likely, naturally, if absorption goes on, is the plumbism to become chronic, and to be associated with paralysis, its prominent sign. Duration of employment among males in file-cutting and china and earthenware, as contrasted, for instance, with that in white lead, is very much longer, and the same could be shown of comparatively new industries, such as electric accumulators and litho-transfers. Thus, in one year the age distribution and duration of employment of those attacked in three of these industries was as follows:
| Industry. | Age Distribution. | Duration of Employment. | ||
|---|---|---|---|---|
| Under 30. | Over 30. | Under 5 Years. | Over 5 Years. | |
| Per Cent. | Per Cent. | Per Cent. | Per Cent. | |
| China and earthenware | 59·4 | 40·6 | 52·2 | 47·8 |
| White lead | 45·7 | 54·3 | 86·8 | 13·2 |
| File-cutting | 22·9 | 77·1 | — | 100·0 |
Persons employed in the manufacture of white and red lead, electric accumulators, paints and colours, and the others named, are exposed essentially to dust from salts of lead, which are readily absorbed. Poisoning, therefore, if precautions are inadequate, will quickly show itself, causing certain workers to seek other employment after one attack. Poisoning thus produced is more likely to induce colic, or, if the dose has been large or the individual markedly susceptible, encephalopathic symptoms, than paralysis. On the other hand, the slowness of the onset of symptoms in the case of brass workers, plumbers, printers, file-cutters, and tinners, is more the result of inhalation of fumes or of dust of metallic lead than of salts of lead; or if the inhalation be of salts of lead, then of these in less amount and over a long period, with, as a result, gradual undermining of the constitution, showing itself in paralysis, arterio-sclerosis, and renal disease. The two factors indicated obviously account for the differences in severity and number of attack between males and females. If second and third attacks are comparatively fewer in females than in males, it follows that, in general, the attack will be less severe also, and this is brought out in the figures. Cerebral symptoms—encephalopathy, to which headache may be added—are more than twice as frequent in females as males. This may be due to idiosyncrasy, but it may very possibly be simply the result of short duration of employment of young workers in processes where dust of salts of lead is incidental.
Attacks generally are most frequent in the first or second year of employment. Thus, of 2,195 attacks reported in the four years 1904 to 1907, as to which sufficient data are given, 898 occurred in the first two years of employment, and of these 672 occurred in the first year—that is, three-sevenths of all the cases were reported during the first two years, and four-sevenths in the whole of the remaining years of employment. It is, unfortunately, impossible to say what is the proportion of attacks among those employed for any given age period. In some factories—as, for example, lead smelting works—the average duration of employment is about thirteen years. The length of employment preceding an attack was made out from reports on cases which occurred in the white lead industry in 1898—a time when a number of new workers were taken on to replace the female labour abolished in June of that year, and conditions as regards removal of dust were entirely different from what they are now. The figures, therefore, can only be considered to have bearing upon incidence under almost the worst possible circumstances. Of 155 attacks, duration of employment was stated to have been less than 1 week in 3, from 1 week to 1 month in 8, from 1 to 3 months in 62, from 3 to 6 months in 44, from 6 to 12 months in 12, and 1 year and over in 26.
Attempt has been made to discredit the value of Section 73 of the Factory Act, 1901, on the ground that the proportion of cases in which some degree of paralysis is present is very high as compared with the extent found by other observers. The points we have laid stress on—(1) duration of employment, (2) varying kinds and amounts of lead dust and fumes—are, we believe, quite sufficient to account for, and give value to, the figures dealt with. To them should be added another factor, though one of less account—namely, the extent to which particular muscles are used. In the case of file-cutters, for instance, there is no doubt that the cramped position of the left hand holding the chisel, and the work thrown on the right in holding the heavy mallet, determine the direction of the paralysis, especially on to the muscles of the thenar and hyperthenar eminences and of the fingers.
There is, however, difficulty in deciding whether such entries on reports as “weakness of arms and legs,” “weakness of arms,” “muscular weakness,” etc., should be interpreted as incipient paralysis.[A] With a disease like lead poisoning showing marked tendency to affect the muscles supplied by the musculo-spiral and other nerves, the only safe course was to include all these terms as equivalent to partial paralysis. [Table V.] on [p. 54] shows close parallelism for the six years.
[A] During the years 1910 and 1911 cases were classified so as to distinguish definite paralysis, as far as possible, from the more indefinite terms referred to, with the result tabulated opposite. We have little doubt that in most of the cases included in columns (3) and (6) some slight degree of paresis was present.
| Form of Paralysis. | 1910. | 1911. | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Paralysis. | Weakness of Arms or Loss of Power. | Total. | Paralysis. | Weakness of Arms or Loss of Power. | Total. | ||||
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | |||
| Arms and legs | - | complete | — | — | — | 2 | — | 2 | |
| partial | 4 | 6 | 10 | 1 | 4 | 5 | |||
| Legs | - | complete | — | — | — | — | — | — | |
| partial | 4 | 4 | 8 | — | 6 | 6 | |||
| Both forearms | - | complete | 15 | — | 15 | 27 | — | 27 | |
| partial | 19 | 30 | 49 | 20 | 44 | 64 | |||
| Right forearm | - | complete | 8 | — | 8 | 5 | — | 5 | |
| partial | 6 | 4 | 10 | 4 | 7 | 11 | |||
| Left forearm | - | complete | 3 | — | 3 | 2 | — | 2 | |
| partial | 2 | 1 | 3 | 1 | 7 | 8 | |||
| Fingers | 3 | — | 3 | 7 | — | 7 | |||
| Neuritis (including numbness of hands or arms) | 5 | — | 5 | 5 | — | 5 | |||
| Other (including paralysis of deltoid, muscles of speech,locomotor ataxy, and general paralysis) | 1 | — | 1 | 4 | 2 | 6 | |||
| 70 | 45 | 115 | 78 | 70 | 148 | ||||
If it is difficult to distinguish rightly all the cases classed as “paralysis,” it is even more difficult to determine what should be included under the term “encephalopathy.” We have limited it to epileptiform seizures, optic neuritis (uncomplicated by epilepsy), and various forms of insanity. [Table VI.] on [p. 54] is interesting as showing how fairly constant the numbers are from one year to another.
Except in the one industry of earthenware and china, in which a return of the number of persons employed according to process and kind of ware has been made on three separate occasions, and in which the reports of the certifying surgeons enable the cases of poisoning to be classified in the same way, it is difficult to determine accurately the attack rate of lead poisoning. Even in the earthenware and china trade many things have to be borne in mind. The poisoning which occurs is not distributed evenly over all the factories. Thus, among the 550 potteries, in the years 1904 to 1908, five potteries were responsible for 75 cases, and 173 for the total number of cases (517), leaving 377 factories from which no cases were reported.
Table V.—Forms of Paralysis: 1904-1909.
| Form of Paralysis. | Total. | 1909. | 1908. | 1907. | 1906. | 1905. | 1904. | |||
|---|---|---|---|---|---|---|---|---|---|---|
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | |||
| Arms and legs | - | complete | 12 | 2 | 2 | 1 | 2 | 1 | 4 | |
| partial | 62 | 13 | 7 | 9 | 13 | 9 | 11 | |||
| Legs | - | complete | 3 | — | — | 1 | — | 1 | 1 | |
| partial | 25 | 5 | 7 | 1 | 3 | 5 | 4 | |||
| Both forearms | - | complete | 162 | 29 | 33 | 29 | 28 | 24 | 19 | |
| partial | 334 | 59 | 70 | 56 | 56 | 43 | 50 | |||
| Right forearm | - | complete | 39 | 11 | 6 | 7 | 4 | 8 | 3 | |
| partial | 62 | 9 | 17 | 14 | 11 | 5 | 6 | |||
| Left forearm | - | complete | 14 | 2 | 2 | 4 | 1 | 3 | 2 | |
| partial | 22 | 4 | 1 | 4 | 6 | 4 | 3 | |||
| Fingers | 36 | 3 | 3 | 7 | 10 | 6 | 7 | |||
| Neuritis (including numbness of hands or arms) | 32 | 7 | 8 | 3 | 3 | 5 | 6 | |||
| Other (including paralysis of deltoid, muscles of speech, locomotor ataxy) | 10 | 3 | 1 | 3 | 1 | — | 2 | |||
| 798 | 147 | 157 | 139 | 138 | 114 | 118 | ||||
Table VI.—Encephalopathy.
| Symptom. | 1911. | 1910. | 1909. | 1908. | 1907. | 1906. | 1905. | 1904. |
|---|---|---|---|---|---|---|---|---|
| Epilepsy | 6 | 16 | 12 | 15 | 14 | 11 | 12 | 15 |
| Optic neuritis | 2 | 3 | 3 | 2 | 3 | 7 | 5 | 4 |
| Mental defect | 5 | 2 | 2 | 1 | 6 | 3 | 1 | 2 |
| Total | 13 | 21 | 17 | 18 | 23 | 21 | 18 | 21 |
The same state of things is found in all the other industries. Particular factories, owing to special method of manufacture or special manner of working, may have an incidence out of all proportion to that prevailing in the trade generally. And it is, of course, control of these more obvious sources of danger by the efforts of manufacturers and the factory inspectors that has led to the notable reduction recorded—e.g., in white lead works and the pottery industry.
Returns of occupiers do not lend themselves readily to exact estimate of the number of persons exposed to risk of lead poisoning, as they do not differentiate the processes, and in nearly all factories in which lead is used some of those returned will not come into contact with it.
In industries, however, in which there is periodic medical examination of persons employed in lead processes an attack rate can be made out. It must be regarded as approximate only, as in the manufacture of electric accumulators, for instance, medical examination is limited to persons employed in pasting, casting, lead-burning, or any work involving contact with dry compounds of lead, whereas the reported attacks include a few persons engaged in processes other than those named.
Table VII.—Attack Rate from Lead Poisoning in the Year 1910 in Certain Industries.
| Industry. | Number of Exami- nations. | Probable Number of Persons employed. | Number of Reported Cases. | Attack Rate per Thousand. |
|---|---|---|---|---|
| White lead | 77,752 | 1,495 | 34 | 22 |
| Red lead | 8,096 | 675 | 10 | 15 |
| Vitreous enamelling | 3,064 | 766 | 17 | 22 |
| Tinning of metals | 1,475 | 492 | 17 | 34 |
| Electric accumulators | 13,065 | 1,089 | 31 | 28 |
| Paints and colours | 19,081 | 1,590 | 17 | 11 |
| Earthenware and china | 78,560 | 6,547 | 77 | 12 |
As has been mentioned above, the accurate information we have of the numbers employed in the several processes in the earthenware and china industry enable us to use the figures for that industry to illustrate, what is certainly true of all other lead industries also, the fact of the relative greater degree of risk in one process than another.
The fall in the number of fatal cases attributed to lead poisoning, as is perhaps to be expected, seeing that the great majority are deaths from chronic lead poisoning, does not run parallel with the diminution in the number of cases. Thus, in the five years 1905 to 1909 the deaths numbered 144, as compared with 131 in the previous five years, although the cases fell from 3,761 to 3,001. We believe this is due to an increasing inclination to attribute chronic nephritis, and even (without sufficient justification in our opinion) phthisis and pneumonia, to lead poisoning on the death certificates of lead workers. Copies of all death certificates on which lead poisoning is entered as directly or indirectly a cause are received by the Chief Inspector of Factories. All of industrial origin are included in the return. Of a total of 264 which could be followed up, encephalopathic symptoms appeared on the death certificate in 38 (10·6 per cent.); Bright’s disease, cerebral hæmorrhage, paralysis, or chronic lead poisoning either alone or as a combination of symptoms closely connected, in 188 (71·2 per cent.); phthisis in 13 (5·0 per cent.); and other diseases, such as pneumonia, etc., in 25 (9·4 per cent.). [Table IX.] brings out the relative frequency in the several groups of industries, and, as is to be anticipated, the different average age at death when due to acute and chronic lead poisoning.
TABLE VIII.—LEAD POISONING IN EARTHENWARE AND CHINA WORKS
(China, Earthenware, Tiles, Majolica, Jet and Rockingham, China Furniture and Electrical Fittings, Sanitary Ware).
| Processes. | Persons employed in 1907. | Cases Reported: Average per Year. | Attack-Rate per Thousand employed: Average per Year. | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1907- 1910. | 1903- 1906. | 1899- 1902. | 1907- 1910.[A] | 1903- 1906.[B] | 1899- 1902.[C] | |||||
| In dipping-house: | ||||||||||
| Dippers | - | M. | 786 | 17 | 18 | 26 | 22 | 23 | 34 | |
| F. | 150 | 6 | 4 | 7 | 40 | 30 | 68 | |||
| Dippers’ assistants | - | M. | 463 | 3 | 3 | 7 | 7 | 7 | 15 | |
| F. | 397 | 13 | 18 | 17 | 33 | 46 | 45 | |||
| Ware-cleaners | - | M. | 115 | 1 | 2 | 3 | 9 | 20 | 30 | |
| F. | 461 | 15 | 18 | 30 | 33 | 41 | 65 | |||
| Total | - | M. | 1,346 | 21 | 23 | 36 | 15 | 17 | 27 | |
| F. | 1,008 | 34 | 40 | 54 | 34 | 42 | 58 | |||
| Glost-placers | - | M. | 2,291 | 16 | 12 | 33 | 7 | 5 | 14 | |
| F. | 120 | 1 | 1 | 1 | 8 | 10 | 14 | |||
| Majolica-painters | - | M. | 28 | — | — | — | — | — | — | |
| F. | 358 | 6 | 8 | 10 | 13 | 14 | 20 | |||
| Ground-layers | - | M. | 58 | 1 | — | 1 | 17 | — | 17 | |
| F. | 157 | 1 | 1 | 4 | 6 | 5 | 13 | |||
| Colour and litho dusters | - | M. | 14 | — | — | — | — | — | — | |
| F. | 143 | — | 1 | 4 | — | 7 | 33 | |||
| Enamel colour and glaze blowers | - | M. | 51 | — | — | 1 | — | — | 36 | |
| F. | 288 | 3 | 3 | 2 | 10 | 14 | 12 | |||
| Colour-makers and millers and mixers of glaze or colour | - | M. | 371 | 5 | 5 | 6 | 13 | 13 | 17 | |
| F. | 55 | 1 | 1 | 1 | 18 | 48 | 114 | |||
| Other persons in contact with lead | - | M. | 327 | 2 | 1 | 2 | 6 | 5 | 11 | |
| F. | 132 | 1 | 2 | 4 | 8 | 21 | 75 | |||
| Grand total | - | M. | 4,504 | 44 | 41 | 80 | 10 | 9 | 19 | |
| F. | 2,361 | 45 | 57 | 80 | 19 | 25 | 37 | |||
| (M. and F.) | 6,865 | 89 | 98 | 160 | 13 | 15 | 25 | |||
[A] Calculated on return of employment for 1907.
[B] Calculated on return of employment for 1904.
[C] Calculated on return of employment for 1900.
The statistical evidence from death certificates published in the decennial supplements of the Superintendent of Statistics[2] is of significance, not only in enabling comparison to be made between one industry and another, in regard to mortality from lead poisoning, but also in determining the other causes of death most frequently entered on death certificates of lead workers, and therefore, if they are in high excess, as compared with male workers generally, they are to be ascribed with some degree of certainty to deleterious effects of lead on some of the principal organs. Thus, in [Table X.] a list of occupations is given in which the mortality from plumbism in the years 1900 to 1902 was double or more than double the standard. It represents the mortality which would occur if the male population in the particular industry had exactly the same age population as that of “all males.” Further, the annual mortality among “all males” is taken as 1,000, and that of males engaged in the several industries is stated as a proportion of this. This “mortality figure” of 1,000 is made up of the mortality from various causes (of which only those considered to bear upon lead poisoning are given in the table) in the proportion stated.
The contention that, because lead workers die from certain diseases more frequently than “all males,” such diseases must be the sequelæ of lead poisoning is untenable unless other recognized causes of the diseases in question have been excluded. For excess of deaths from phthisis and respiratory diseases the conditions of work and exposure to inhalation of mineral and metallic dust or vitiation of atmosphere, in pottery, spelter, printing works, and file-cutting workshops, sufficiently account. The figures, indeed, take no account of this, and their value, in some at any rate, is still further diminished by the very large number of occupations (several involving no contact at all with lead) included in the headings. With exception of the strikingly greater proportion of deaths among lead-workers from Bright’s disease, the figures are too contradictory to draw deductions from as to what are “sequelæ” of lead poisoning. But this figure—160, as compared with 35 for all males—is confirmatory evidence, if any were needed, that chronic Bright’s disease is a sequela. And, from the pathology of lead poisoning, we believe that the granular condition of the kidney is due to the sclerotic change brought about in its substance by microscopic hæmorrhages. We have very little evidence indeed in man that this interstitial change is set up or preceded by an acute tubal nephritis. While we do not deny that there may be some parenchymatous change associated with lead poisoning, we do not believe that it is of the kind which gives rise to the large white kidney, and we should therefore exclude such disease as a sequela. But if chronic Bright’s disease is admitted, the train of symptoms associated with it—notably arterio-sclerotic changes resulting in cerebral hæmorrhage and albuminuric retinitis—must be admitted also. Unless it were established that granular nephritis were present in a lead-worker before commencement of lead employment, we think it would be useless to endeavour to prove that the condition was independent of lead, despite its comparative frequency as a cause of death apart from employment.
TABLE IX.—MAIN SYMPTOMS APPEARING AS THE CAUSE IN 264 DEATH CERTIFICATES OF LEAD POISONING.
| Industry. | Encepha- lopathy. | Bright’s Disease. | Cerebral Hæmor- rhage. | Paralysis. | Lead Poisoning. | Phthisis. | Pneumonia, Bronchitis, Heart Failure, Colic, Hernia, and Aneurism. | Total. |
|---|---|---|---|---|---|---|---|---|
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) |
| Smelting of metals | 1 | 6 | — | 3 | 5 | 1 | 1 | 17 |
| Brass works | — | 3 | — | 1 | 1 | — | 1 | 6 |
| Sheet lead and lead piping | — | 1 | — | — | 1 | — | 1 | 3 |
| Plumbing and soldering | 2 | 3 | — | 1 | 2 | 1 | 2 | 11 |
| Printing | 3 | 3 | — | 2 | 5 | 1 | 3 | 17 |
| File-cutting | 1 | 11 | 2 | 2 | 2 | 1 | — | 19 |
| Tinning and enamelling | — | 1 | — | — | 1 | — | — | 2 |
| White lead | 13 | 2 | 2 | 4 | 2 | 1 | 3 | 27 |
| China and earthenware | 8 | 24 | 14 | 3 | 6 | 2 | — | 57 |
| Glass-cutting | 1 | 6 | — | — | 1 | — | 1 | 9 |
| Electric accumulators | 2 | 1 | — | 1 | — | — | 2 | 6 |
| Paints and colours | 4 | 1 | — | — | 2 | 1 | 3 | 11 |
| Coach-making | 1 | 8 | 5 | 6 | 10 | 3 | 4 | 37 |
| Ship-building | 1 | 4 | 1 | — | 1 | 1 | — | 8 |
| Paints used in other industries | — | 3 | 1 | 4 | 6 | 1 | 2 | 17 |
| Other industries | 1 | 2 | 1 | — | 11 | — | 2 | 17 |
| Total | 38 | 79 | 26 | 27 | 56 | 13 | 25 | 264 |
| Average at death | 32 | 43 | 47 | 43 | 44 | 38 | 40 | — |
TABLE X.—COMPARATIVE MORTALITY FROM SPECIFIED CAUSES AMONG MALES ENGAGED IN CERTAIN OCCUPATIONS: 1900-1902.
| Occupation. | Causes of Death. | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| All Causes. | Alco- holism. | Gout. | Phthi- sis. | Diseases of the Nervous System. | Diseases of the Circu- latory System. | Diseases of the Respi- ratory System. | Diseases of the Diges- tive System. | Bright’s Disease. | Other Diseases of the Urinary System. | Plumbism. | Acci- dent. | |
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) | (11) | (12) | (13) |
| All males | 1,000 | 16 | 2 | 186 | 105 | 145 | 174 | 57 | 35 | 17 | 1 | 59 |
| Printer | 994 | 8 | 3 | 300 | 111 | 125 | 131 | 55 | 42 | 15 | 2 | 21 |
| File-maker | 1,700 | 14 | — | 387 | 225 | 198 | 325 | 78 | 134 | 26 | 56 | 46 |
| Copper-worker | 1,090 | 7 | 3 | 162 | 104 | 139 | 357 | 45 | 24 | 21 | 3 | 51 |
| Lead-worker | 1,408 | 38 | — | 165 | 134 | 222 | 309 | 14 | 160 | — | 102 | 52 |
| Coach-maker | 824 | 4 | 4 | 129 | 113 | 129 | 150 | 46 | 39 | 14 | 8 | 29 |
| Earthenware | 1,493 | 8 | — | 285 | 131 | 219 | 473 | 57 | 33 | 20 | 10 | 33 |
| Glass | 1,260 | 7 | 4 | 283 | 131 | 177 | 268 | 54 | 58 | 16 | 8 | 31 |
| Painter and plumber | 1,114 | 13 | 8 | 213 | 133 | 105 | 168 | 31 | 74 | 20 | 23 | 50 |
Other conditions which might readily be admitted as sequelæ are optic neuritis, following on an attack of encephalopathy. No general statement can be made in regard to mental and nervous diseases, gout, pernicious anæmia, as sequelæ, as each must be considered in relation to the evidence adduced in the particular case, and after exclusion, in the first two, of syphilis as a cause.
The distinction between causation and association has to be borne in mind before admitting as sequelæ of lead poisoning diseases of bacterial origin, such as phthisis or pneumonia, or any disease to which the affected person may be thought to have been rendered more prone by reason of lead employment. The contention that a person may have been debilitated by lead poisoning is no proof that the enfeeblement of the constitution was the cause either of the bacillus gaining entrance into the lung or of the ultimate fatal issue from the engrafted disease. Such assertion in every case must rest on supposition. Evidence that lead employment predisposes to phthisis is not necessarily made stronger, in our opinion, by existence during life of clinical symptoms, or, in their absence, of detection of lead in the tissues post mortem.
In classifying causes of death, the general rule should be to select, from the several diseases mentioned in the certificate, the disease of the longest duration. Exceptions to this rule are that definite diseases ordinarily known as constitutional diseases should have preference over the other diseases mentioned. After thirty-five years of age, certificates of death from lead poisoning are almost always filled in in association with other diseases which are the usual causes which lead to mortality generally. But neither phthisis, nor pneumonia, nor any acute disease of the heart or lungs, nor valvular disease of the heart, nor, indeed, any acute febrile condition, can have direct relation with—i.e., be a sequela of—lead poisoning.