The fatty tissue of the long bones is in many instances replaced by a red marrow resembling that of the short bones of the adult and the entire osseous system of the infant. This was first noticed by Pepper in 1875,82 and has since been frequently observed. The color is usually of a reddish-purple when fresh, becoming a bright red on exposure. Sometimes there is a grayish-red appearance. It may not be universally distributed in the long bones, and the change would appear to proceed from the trunk toward the periphery—a direction the reverse to that in which the red marrow of the child becomes fatty. In many cases the marrow has been found normal; in others, the change known as gelatinoid has been observed. In five Montreal cases I found the marrow of the long bones lymphoid, in one gelatinoid, and in two the long bones could not be examined. It must be borne in mind that the short and flat bones of the adult contain a red lymphoid marrow mixed with a variable amount of fat, in which nucleated red corpuscles can always be found.
82 American Journal of Medical Sciences, lxx.
The brain and cord present an intensely anæmic appearance; the membranes are relaxed and oedematous, and petechiæ may exist. The convolutions are often wasted, and the amount of cerebro-spinal fluid increased. No important changes have been found in the substance.
The ganglia of the sympathetic system have been examined by Queckett in one of Addison's cases and found fatty. Wilks and others have found them normal. Brigidi83 has described an increase in the interstitial tissue and pigmentation of the cells. In two instances I found nothing abnormal. Sasaki84 has described marked degenerative changes in Auerbach's and Meissner's plexuses in two cases of pernicious anæmia.
83 London Med. Record, 1878.
84 Loc. cit.
The kidneys are usually pale and without special change beyond the fatty degeneration. Quincke has found the amount of iron increased. The suprarenals have in several instances been found very small. The sexual organs show no constant changes.
PATHOLOGY.—Under the general subject of Anæmia the pathology has been discussed at sufficient length. After excluding pregnancy, parturition, lactation, and inanition cases, as partaking more of the characters of secondary anæmia, we can recognize three groups of cases: First, those in which the bone-marrow has been found extensively affected—cases of anæmia medullaris; second, cases in which a primary atrophic change in the mucous membrane of the stomach appears to have been the starting-point of the trouble; and, third, cases in which after death no special changes have been found sufficient to explain the anæmia. To the latter the term idiopathic is applicable, and possibly they may be instances of hæmophthisis due to increased destruction of the corpuscles from causes unknown at present.
DIAGNOSIS.—A case in which anæmia comes on without obvious cause and without enlargement of the spleen, and progressively increases in spite of remedies, diet, change of air, etc., may be regarded as one of an idiopathic or essential character. If the case goes on to a fatal termination, the designation of pernicious is appropriate. I would place some reliance on the microscopical examination of the blood, and would consider the presence of microcytes with great irregularity in the ordinary red corpuscles strong confirmatory evidence. The absence of wasting, the peculiar lemon tint of the skin, the occurrence of epistaxis and retinal hemorrhages, would render a diagnosis certain.
In that class of cases so well described by Fenwick,85 Nothnagel,86 and Nolen,87 in which there has been an interstitial inflammation of the gastric mucosa and atrophy of the glands, the question has not yet been decided how far this condition is to be considered causal, and how far a part of the general disturbance of nutrition. The clinical picture may be identical with that of idiopathic anæmia, and in some of the cases the gastric symptoms have been so marked that the relation of the atrophy and the anæmia has evidently been that of cause and effect. And yet in these cases there does not appear to be the pronounced emaciation of inanition anæmia. In other instances the diarrhoea and chronic intestinal trouble may, with or without gastric participation, bring about a similar condition.