CONTAGIOUS ABORTION.
Definition: Premature expulsion of non-viable fœtus. Synonyms. Susceptible animals: cows, goats, sows, mares. Accessory causes: Ice cold drinks at periods of ovulation, frozen aliments, ice cold bath or rain storm, mechanical injuries, unwholesome fermentescible food, indigestible foods, close stabling, heavy milking, early breeding, inbreeding, stagnant water, ergot, smut, vegetable irritants or ecbolics, constitutional diseases, irritation of generative organs, death of fœtus, urinary calculi, odor of carcass or carrion, contagion, experimental infection between cows, between mare and cow, relation to omphalitis. Nocard’s streptococci and bacilli, Bang’s bacillus with best growth in two distinct grades of oxygenation, Galtier’s observations, bacterium of the Colon group in America, infection of the calves (pneumonia). Various kinds of infectious abortion. Acquired immunity, variable in different forms. Immunized cow still infecting. Symptoms. Lesions. Abortion in mares. Therapeutics. Prevention: Protection of a sound herd, guarantee with purchase, government control, precautions with male or unimpregnated female, with pregnant. Extinction in a herd, separation, disinfection, disposal of abortion, manure, urine, disinfection of animal, of genital organs, precautions as to service, new born, fields, ewes. Disinfectants, subcutem or in muscles.
Definition. The premature expulsion of the product of conception before it is viable out of the womb. Strictly speaking, a parturition in which the offspring is so far matured as to be viable is a premature parturition, while if it is non-viable it is an abortion. Vulgarly, however, as applied to herds, the term is used for any early parting with the fœtus. In this wider sense infectious abortion is the premature expulsion of the fœtus owing to an infectious catarrh of the womb, transmitted from one animal to another by the transference of the microbe.
Synonyms. Infectious Abortion, Enzoötic Abortion, Epizoötic Abortion.
Animals Affected. Abortion is most common in cows, and less frequent in ewes, goats, sows and mares.
Forms and Accessory Causes of Abortion. It was formerly supposed that abortion in herds was mainly due to mechanical and chemical agencies acting injuriously on the system, and in adopting the explanation of a particulate, transferrable, infectious agent for the habitual widespread forms of the disease, we should not forget these accessory causes, many of which by themselves cause sporadic abortions without the intervention of an infectious element.
The free consumption of ice cold water by the healthy dam causes active gastro-intestinal peristalsis and vigorous movements of the advanced fœtus, which can be seen or felt in the right flank, so that this is often resorted to, to determine whether the animal is pregnant or not. If this is frequently repeated or carried to excess in susceptible animals it will at times cause abortions. As in all other cases of mechanical or physiological disturbance, this is most operative at those periods of constitutional changes, which if the animal had been unimpregnated would have brought about ovulation and œstrum.
The greedy ingestion of cold aliments, like frozen roots, or green vegetation covered with hoar frost, may have a similar action, the more so that such aliments are extremely fermentescible and liable to cause tympany and undue pressure on the gravid womb.
Even without ingestion, exposure to cold rain or snow storms or the plunging in ice cold water tends to produce excessive peristalsis and fœtal movements and thereby prove injurious.
Mechanical injuries to the abdomen as crushing by a gate, kicks, hooking with horns or tusks, hounding with dogs, riding of each other when a cow is in heat, are liable to produce congestions, detachment of fœtal membranes, and even death of the fœtus.
Very fermentescible foods like those following a wet season or bad harvest, or those made of the leafy albuminous plants like lucerne (alfalfa), sainfoin and clover, act injuriously in the way of causing tympanies and compressions, but it must also be recognized that we are here dealing with fodders abounding in bacterial ferments, and that some of their products may act physiologically as ecbolics, even if the bacteria themselves do not colonize the genital passages as infections.
Insufficient food or very innutritious forage, too close stabling, heavy milking, early breeding (dam or sire), inbreeding, are liable to lower the general stamina and throw the system more open to the action of other factors.
Stagnant, corrupt drinking water has been charged with causing abortion, and the trouble has ceased when it has been withdrawn, but it is difficult to estimate its value in different cases—disturbing digestion, fermentation, poisoning, or introducing of actual infection.
Ergoted grasses and smut in maize, wheat or oats, have been often charged with wide spread abortions, and though each has in turn been administered in large and continuous doses without causing abortion, this does not invalidate the many cases in which it manifestly had that effect, nor does it show that obstetricians have been mistaken in their almost immemorial trust in ergot as an ecbolic. It must be recognized, however, that grown under different conditions, of sunshine and shade, and harvested at different stages of its development, ergot varies greatly in its physiological action, as it does also from having been overkept and thus one specimen is effective or dangerous while another is absolutely ineffective. The specific action of the alkaloids in determining contraction of involuntary muscular fibre, is seen alike when used medicinally and when acting as an accidental toxic agent in causing spasms, nervous torpor or paralysis, delirium; gangrene of the feet, tail or tip of the ear; or contraction of the womb and expulsion of its contents. Like other agents mentioned ergot is at times an active ecbolic when coöperating with other similarly operating agencies.
Irritant vegetables of various kinds are to be dreaded. Such as act on the bowels and kidneys, keeping up a constant diarrhœa and diuresis, are quite liable to cause abortion in susceptible subjects. Savin, tansy and rue have obtained a bad reputation in this sense.
Cotton root bark is an active ecbolic, but is not likely to harm animals unless deliberately administered.
Impaction of the rumen or manifolds, and obstinate constipation with the resulting straining or compression must be named as an accessory cause.
Severe constitutional diseases, especially the infectious fevers, aphthous fever, lung plague, rinderpest, etc., are occasional causes of abortion.
It may be brought about by direct irritation of the womb, as in ovariotomy or dilatation of the cervix, or again by death of the fœtus through twisting of the umbilical cord.
Where cattle are subjected to dry winter feeding, in the absence of ensilage or roots, on the magnesian limestones, small calculi in the kidney are almost the rule in winter and the irritation caused by these conduces to abortion.
Nor must mental influence be altogether ignored. Cows and even mares are exceedingly sensitive to the smells of decomposing animal matter, as seen every day in the vicinity of abattoirs, or in case the carcass of one of their fellows has been opened, and not infrequently in connection with carrion, and the occurrence of abortions after such excitement has been frequently noticed. Cases are on record of specially susceptible cows having had active labor pains, from being with another cow at the time of parturition. Shepherds have noticed that violent thunder storms have been followed by numerous abortions in the flocks.
The Contagious Form. Any of the usual causes of sporadic or accidental abortion may coöperate with the true infectious element and give unusual energy to it, yet it is of the utmost importance to recognize the contagion as the essential cause in all cases in which it is present. This can usually be done by a careful inquiry into the history of the outbreak.
When a herd has been continuously healthy up to the date of the introduction of a cow brought from a herd where abortion has been prevailing, and when following her arrival, one after another of the original members of the herd abort, without any apparent cause in the way of change of feed, water, barn, stalls, or general management, the evidence of the introduction of contagion by the cow in question is very circumstantial and forcible. If pregnant cows standing next to the new cow, or near to her, abort, the argument for contagion is still further corroborated. If the trouble continues in the herd year after year, attacking fresh animals some months after their purchase, the case becomes still stronger.
Or if a cow from a healthy herd is sent to a bull, that has been allowed to serve an aborting cow, and if the resulting pregnancy in the first cow is terminated by abortion, and if this is followed by successive abortions in the previously healthy herd, we may reasonably conclude that we are dealing with the infectious form. If no other appreciable cause for the trouble can be found we may reasonably conclude that this was the channel for infection.
Or a bull is brought from a herd where abortions have taken place, and some time after his arrival, the cows of the previously sound herd begin to abort, the first cases being in those that the new bull has served. The occurrence is manifestly the result of contagion.
Or a newly purchased cow aborts, and is disposed of in consequence, and another cow, placed in the same stall, in due time aborts also, and others follow in succession, especially those that stood next or near to the stall in question. Everything points to an introduced infection.
An indefinite number of other exemplary cases might be adduced, each varying from the last, but all agreeing in this, that the evidence of infection stands out prominently and unmistakably. The infecting material may have been carried by the tail, tongue, soiled stall, gutter, rubbing post, fence or other object, yet the fact of contagion can be demonstrated with reasonable certainty.
These conclusions have been repeatedly affirmed by actual experimental transmission. The Scottish abortion committee found that healthy pregnant cows often escape, though standing near or even next to an aborting one, but that when a piece of cotton wool was inserted into the vagina of an aborting cow for twenty minutes and then transferred to that of a healthy one, the latter invariably aborted. Galtier found that when the infecting vaginal mucus of the aborting cow was transferred to the same passage of the healthy pregnant one, abortion took place in the latter. He succeeded in conveying the disease in this way from cow to sow, ewe, goat, rabbit and Guinea pig, and found that growth in the body of the rodent intensified its virulence, so that it could then be successfully inoculated on the mare, bitch and cat.
Bang subjected two cows, from healthy herds and three months pregnant, to repeated injections of the products of the culture of his abortion bacillus in serum glycerine bouillon. Three injections were made on April 14, May 23 and June 4, and on June 24 one cow aborted. The other sickened and when killed was found to carry a dead fœtus. Pure cultures of the abortion bacillus were found in the fœtal membranes and liquids of both animals.
Casual Infections. In a case which came under the observation of the present writer, a family cow kept in a barn where no abortion had previously occurred, was taken for service to a bull in a herd where abortion was prevailing, and though she was only present at the latter place for a few minutes, she aborted in the sixth month.
Another cow from the same aborting herd, was taken into another herd at a distance of two miles, where abortion had been unknown up to that time, and some months later the cow standing in the stall next to her aborted. The remainder of this herd was sold soon after, so that the further progress of the disease was not traced.
Tobiassen quotes the case of a cow from an aborting herd, which calved a fortnight before the regular time. The calf was at once sent to another farm where no abortion had occurred, and placed in the same building with the pregnant cows, all of which later aborted. The outbreak thus started lasted for several years.
Jansen as quoted by Sand, reports the case of a cow from an aborting herd having been taken into a herd that had been previously quite free from the disease. Soon after her arrival she aborted, and later, cows in the same herd aborted. The owner kept the matter secret and sent his cows to a neighbor’s bull for service, with the result that for two years abortion prevailed among the cows served by this bull.
J. R. Jansen reports that a cow brought from an infected farm, for fattening purposes, proved to be pregnant and finally aborted, and that 24 of the pregnant cows on the same farm aborted in the same year.
Mörck relates how a cow that had aborted a fortnight previously was taken to a farm where abortions had never been known. She aborted during her next gestation and so did the rest of the herd, 9 in number.
Christensen records the occurrence of a general abortion in a previously healthy herd, members of which had been sent for service to the bull of a neighboring aborting herd.
Nygaard reports that a bull from a healthy herd, but which had been allowed to serve some cows from a neighboring infected herd, was sold to go on a previously healthy farm, where he was put to 14 cows only. Of these 12 aborted, and the complement of the herd, beyond the 14 cows, put to another bull, remained well.
In each of these cases the environment of the animals and the conditions remained the same, the one appreciable cause of the outbreak being the contact with an animal from an aborting herd.
Experimental Infection. Braüer led the way by transferring in 11 instances the vaginal mucus of aborting cows to the vagina of healthy ones. The resulting abortions occurred from the 9th to the 21st day after inoculation. Lehnert repeated this on two cows, the abortions taking place on the twelfth and twentieth days respectively. Trinchera transferred the purulent vaginal mucus of an aborting cow to the vaginæ of healthy ones, determining in the latter, in 9 to 13 days, abortion attended by suppurating vaginal catarrh. He secured similar results by using the material scraped from the surface of the chorion of an immature fœtus.
The Scottish Commission (Woodhead, McFadyean and Aitkin) placed a healthy pregnant cow in an aborting herd, and on two successive days lodged in her vagina for twenty minutes a piece of cotton wool soaked in the vaginal mucus of a recently aborted cow. Within a month abortion threatened, and on the seventieth day a seven months calf was dropped.
In a second experiment a cow, six months in calf, was taken from a healthy herd and placed in an aborting dairy herd and a quantity of vaginal mucus from a cow that had recently aborted was injected under the skin of the vagina. She calved prematurely at the end of the eighth month of gestation.
Williamsen, while treating a herd for abortion, took a piece of the afterbirth of one of the aborting cows and rubbed it on the vagina of a healthy cow of his own, which had a habit of carrying her calf fourteen days over time. Five days after she had premature parturition.
He took a fragment of the fœtal membrane from the cow just named and rubbed it on the vagina of a pregnant cow condemned for tuberculosis. In seventeen days the cow aborted.
Though not started as an experiment, the writer may name the general extension of abortion from one or two cows in a tuberculous herd after they had been tested with tuberculin. Cases of this kind are doubtless much more common than has been supposed.
Kilborne and Smith developed suppurating vaginal catarrh in cows and mares by inoculating them with the artificial cultures of bacilli obtained from the vaginal secretions of aborting mares.
Turner made cultures from the ovaries of aborting mares, and others from the genital organs of foals suffering from omphalitis, and produced abortions in pregnant mares by injecting with the same.
Pathology. Bacteriology. Franck attributed the disease to leptothrix vaginalis, but subsequent observers failed to substantiate this.
The Scottish Abortion Commission isolated five different bacteria from the abortion membranes and vaginal mucus, but failed to identify any one of these as, by itself, capable of causing the disease.
Nocard found in the fibrino-purulent matter between the chorion and womb in aborting animals a micrococcus occurring singly or in chains, and a short, delicate bacillus isolated or in pairs. From the absence of evil effects between pregnancies he opines that the germs grow in the membranes only, and do not affect the womb nor the general system. He recognizes, however, that they survive in the womb from one pregnancy to another in the complete absence of these membranes.
Galtier, on the contrary, conveyed the disease variously by the inoculation or feeding of the milk or abortion membranes to sheep, goat, pig, rabbit and Guinea pig, and accordingly claims that the general system of the pregnant animal is infected, and that the germs can be conveyed through the blood to the womb. In deducing this from feeding experiments he appears to make too little account of the ready infection through proximity of the anus and vulva.
Chester, of Delaware Agri. Experiment Station, found in the fœtal membranes of aborting cows a bacillus, which in form and habits of growth closely resembled the bacillus coli commune. In the fermentation test, however, it showed a marked difference.
Inoculated on rabbits it did not prove fatal. Injected into the vagina of a healthy pregnant cow it caused slight catarrhal discharge for four or five days, but the calf was carried to full time six and a half months later.
Bang found in aborting cows, between the womb and fœtal membranes, a considerable odorless, gelatinoid, liquid exudate, and some pus cells. There was active catarrh of the uterine mucosa which often carried the disease over into the next pregnancy. In the exudate he found a number of very minute nonmotile bacilli (1 to 3μ), which stained readily with aniline colors, excepting in a vacuole or nucleus which was less deeply pigmented. This bacillus grew well in serum glycerine bouillon, and more sparingly in serum-gelatine agar. In the latter it showed a remarkable peculiarity which serves to identify it readily from other microbes, in two successive zones of luxuriant growth at two different depths, with an intermediate clear zone, in which little or no growth took place. It seems to prefer a greater or lesser supply of oxygen (21 or 90:100) without being able to adapt itself to the intermediate condition. As already stated it produced abortion in the cow in 21 days after injection into the vagina. It also induced uterine catarrh and abortion in ewes, goats, rabbits, Guinea pigs and mares when injected into the vagina. From the vagina it usually reaches the womb, but not always. In several cases in which it was injected subcutem or intravenously it caused hyperthermia, and was later found in abundance in the interior of the womb and fœtal membranes, and in the bowels of the fœtus. The microbe is, therefore, capable of living in the blood and affecting the womb by whatever channel it may enter the system.
V. A. Moore and the present writer made a series of experiments at the New York State Veterinary College. In the fœtal membranes and uterine mucus of a number of cows, aborting in different parts of the State and therefore long distances apart, we found a bacillus that in form and culture-experiments closely resembles bacillus coli commune. This was nearly always in pure cultures, and in the few cases showing other microbes, these were only such as inhabit the healthy vagina. Our bacillus was never found in the womb nor fœtal membranes of cows that had calved at the full period in healthy herds. It agreed in most respects with the bacillus found by Chester, but differed somewhat in fermentation tests. It differed also in proving fatal to rabbits when inoculated on these animals. Injected in the form of cultures into the vagina in three old pregnant cows it continued to live on the mucosa, producing more or less catarrh and muco-purulent discharge in the different cases, yet all three carried the calf to full time, one having calved on the 123d day after injection, the second on the 167th, and the third on the 190th.
The results obtained at the Delaware College Experiment Station and the New York State Veterinary College, do not differ so seriously, as either one does from those obtained in Europe, by Nocard, Bang, and the Scottish Abortion Committee. The facts that the same germs were found, either in pure cultures, or exceptionally, along with the normal microbes of the healthy vagina, in the womb, and fœtal membranes of every aborting cow, that they were never found in the healthy cow which had calved at full time, and that the generative passages were the seat of a catarrh, alike in the cows that aborted and in those that were inoculated with the abortion discharges, but did not themselves abort, are all but conclusive that this microbe is the essential cause of the abortion.
The single objection to this view, namely that the inoculated cows did not abort is explained by the fact that in the New York abortions it is the rule that the calf is carried six or seven months from the date of impregnation (the date of the presumptive infection) to that of abortion. It is to be further borne in mind that our experimental cows were old, and may have passed through the disease before and become in some measure immune, that they were dry during the experiment, and were subjected to no extraneous excitement that would predispose them to abort. The presumption is that had the experiments been started earlier in the gestation, the abortion would have come in due time. The microbe maintained its hold on the mucosa and continued to advance up to and beyond parturition.
Another distinction of the European abortions, is in the presence of the microbe in European form in the digestive organs of the calf, and that the viable calves of infected cows are liable to die of intestinal disorders a few days after birth. Galtier, the Marquis de Poncius and Pry insist strongly on this. On a farm on the estate of the Marquis, where abortion had prevailed for twenty years, the calves of infected cows show at birth, or very shortly after, symptoms of broncho-pneumonia and of a complication of nervous disorders. They are breathless, wheeze, discharge from the nose, cough, scour, have convulsions or other nervous trouble. A large proportion of such calves die; and their lungs are found in part red, consolidated and devoid of air and the bronchia contain a muco-purulent product. Lesions denoting inflammation of the serosæ of the lungs, liver and intestines are common. This coincidence of a fatal disease in many of the surviving calves is exceptional among the aborting herds of New York.
In noting the evidence of a wide difference between the prevalent American and European forms of abortion in cows, one should be prepared to go farther, and accept if need be, still other distinctive forms in each of the two continents. Any catarrhal condition of the uterine mucous membrane, is a recognized hindrance to conception, and cause of abortion, and we must recognize that the forms of invasion of the womb by pus microbes are as numerous as there are irritant germs capable of living in the membrane. The question as to how many of these can produce contagious abortion is to be determined by the susceptibility of the membrane to irritation by each germ, and whether the latter can retain all its power of survival and virulence in passing from one animal to another. The presumption is, therefore, in favor of a variety of forms of contagious abortion, each due to its own specific microbe or microbes, rather than of a single unvarying type of the disease. In some the affection appears to be a purely local one (American), the microbe being confined to the genital or genito-urinary mucosa, whereas in others the microbes (Bangs’, Galtier’s, etc.) live also in the blood producing a general infection.
Two great types at least have been demonstrated in Europe and America. Whether future investigation shall show the presence in one of these continents of the types as yet only known in the other, remains to be seen. If the particular forms should turn out to be limited to different continents we are at once confronted with the necessity of an international sanitary quarantine, and inspection. Matters are bad enough now in our dairying districts, but if we are to be open to the importation of new types of abortion, which do not mutually immunize against each other, but which may be taken one after another in succession through a series of years, they may easily become incomparably worse.
Acquired Immunity. The question of persistent abortion year after year, in the same animal, is most important. If a first contagious abortion entails a second, a third, a fourth and a fifth in the same animal, in as many successive years, then manifestly the preservation of such animal is a most wasteful economy, altogether independently of the danger of her transmitting the infection to healthy stock. If, however, she herself becomes immune after a first or second abortion, it may be profitable to retain her for milk production or breeding, provided that she can no longer infect susceptible cows with which she must come in contact.
Acquired immunity of the individual cow is the rule after one or two abortions caused by the microbes with which we are at present most familiar. There are exceptions to this rule due to special nervousness and excitability of given cows, which tend to an indefinite repetition of the abortion, under the stimulation of pregnancy, of the continued presence of the microbe, or of some local disease (tubercle, tumor, parasite, etc.) of the ovary, womb or peritoneum. Yet statistics show that this only applies to a small proportion of cows and these the most nervous and excitable. The tendency toward insusceptibility to the deleterious action of the germ, which may still be present, is in the cow as a rule greater than the disposition toward a nervous encrease of the susceptibility. The difficulty of reaching a conclusion on this point depends on the fact that stockowners very commonly dispose of aborting cows, and as the freshly bought cows are usually attacked sooner or later, it is too confidently assumed that the old cows also would have continued to abort had they been retained. Many years ago, however, observant New York dairymen had noticed that the same cow rarely aborted over three years in succession, and in the great majority of cases not over two. The owner of a large herd, who has had much experience with the disease, assures me that the rule has been, that a cow did not abort with him a second time. The continuous abortion in a herd was mainly among newly purchased cows and others that had not been previously attacked, including heifers carrying first calf. The same is in a measure true of the European abortions.
Nocard says that after three to five years there is an acquired immunity. Only heifers and the cows that have been recently bought in, abort.
Penberthy, speaking of England, says that in case of repeated abortion in the same cow, the calf is carried longer each successive year until it comes to its full term.
Sand, in his symposium of the experience of Danish veterinarians, says it is quite exceptional that a cow should continue to abort, but outbreaks of abortion disappear spontaneously if no new cows are brought in.
Bang refers to a herd of 200 head of which 83 aborted in their first pregnancy, and of these only 20 aborted in the second, while 7 failed to breed. Counting the latter as having aborted, this amounts to less than one-third, while over two-thirds of the cows that aborted in the first gestation carried the calf to full time.
Paulsen quotes the case of a herd of 16, 7 of which aborted after service by a bull in an aborting herd. One of the seven was sold, but the remaining six all went full time in the following year.
Mörck records the case of a herd of 16 cows, the majority of which aborted in the same year. All the aborting cows were sold and fresh ones purchased. Next year the new stock aborted together with some of the cows that had been held over. He continued this course for eight years without any improvement, and then decided to keep the aborting cows as well as the others. In two years the affection disappeared from the herd.
Such small herds, in which all become early infected, and in which there is no further opportunity for the infection of susceptible animals (cows not yet infected, heifers in first gestation, new purchases), furnish a better opportunity than do large herds, to trace the acquirement of tolerance.
In a question of this kind, one must allow for variations in the different types of abortion caused by various microbes, but in the forms with which we are familiar in Europe and America, the acquired tolerance of the individual can be counted on with great confidence. It has indeed been largely traded upon by purveyors of antiabortion nostrums who promise to cure the individual cow, to which alone their drugs are administered. Two evils result: the stock owner’s money is paid for that which unaided, nature would have accomplished for him; and attention is withdrawn from the real necessity of the case, the prevention of the infection of freshly introduced animals. The nostrum vender thus secures for himself a growing market, as the yearly production of fresh cases in the same herds, appears to demand a constant use of the agent which appeared to work so well in the earlier ones.
Immunized animal still infecting. The cow that no longer aborts is not, therefore, a safe member of a herd. As an individual animal she has become resistant to the pathogenic influence of the germ, she is invulnerable to it to the extent that she no longer aborts, but her system and generative passages have acquired no such active bactericidal power over the microbe as to lead to its speedy destruction. The genital passages, once colonized, continue to be a field of growth of the bacillus long after its power to cause abortion in that particular animal has passed. Analogous cases can easily be quoted from the field of pathology. The horse that has apparently recovered from dourine still conveys the disease to others with which it has sexual congress; the recovered syphilitic person is by no means eligible for marriage; the recovered pig continues to carry the infecting swine plague bacillus in its air passages. In short, it is the rule that the immunized animal can with safety to itself carry a germ that readily infects its nonimmunized fellows.
In the case of infectious abortion this is one of the most dangerous elements, as the apparently healthy recovered cow receives no attention in the way of separation and disinfection, but is allowed to spread the infection through the bull that serves her in common with other cows and by being sold into new and healthy herds.
Symptoms. Contagious abortion sometimes takes the form of temporary sterility, the animal taking the male at frequent intervals, but failing to conceive. If conception takes place, the abortion is usually deferred until the fœtus has attained a considerable development—in cows till the third or seventh month; in mares till the fourth or ninth month; in ewes or sows till the tenth week.
Often times premonitory symptoms are entirely unobserved. Usually there may be detected some heat and enlargement of the mammæ, with a decrease in the milk yield, or a serous modification of the milk as in colostrum. Still more striking is a muco-purulent discharge from the vulva—opaque, white or yellow—in marked contrast with the perfectly clear, transparent mucus which appears in œstrum. The discharge may be densely white (in mares) or reddish, and may be accompanied by some swelling of the vulva and redness of its mucosa, which is dull, rough and granular, or even the seat of a papillary eruption. There is rarely hyperthermia or other constitutional disturbance, and in some cases the abortion is only discovered by the finding of the fœtus and its membranes in the gutter or pasture. The membranes are, however, not unfrequently retained, becoming offensively putrid. In other cases a muco-purulent discharge persists for a length of time, insuring sterility so long as it lasts, and causing ill health and emaciation. The fœtus is usually born dead.
The lesions are confined to the generative organs. Bang, found an odorless, dirty yellow, flocculent, slimy and more or less watery exudate between the chorion and uterine mucosa involving the connective tissue between the chorion and arachnoid so as to render it thick and friable. These conditions were well marked in the French and English cases, and perhaps somewhat less so in the American, which are habitually slower in reaching the abortion. Bang found the uterine catarrh with the characteristic bacillus in cases in which the calf had been carried to full term, exemplifying the local presence and culture of the bacillus without the usual abortion outcome. The bacilli were occasionally, though not always, found in the body of the fœtus, and in some cases the dead and mummified fœtus was found in the womb, which had not been stimulated to its expulsion. He even found the bacillus in the mummified fœtus, and still virulent, after an apparent seclusion of seven months.