ABSTRACTS.

IS THE BACILLUS OF CONTAGIOUS ABORTION IN COWS PATHOGENIC FOR HUMAN BEINGS?

THE investigations of Schroeder and Cotton, and others, have shown that the bacillus of bovine abortion is often present in the milk of apparently normal cows, tnat it is sometimes present in great numbers, and that the infected milk may be pathogenic for guinea-pigs when 5 cc; are inoculated intraperitoneally. That this bacterium is the causative organism of infectious abortion in cattle, and that it will produce serious lesions in guinea-pigs and affect other experimental animals is generally admitted. These facts have suggested that milk containing this organism may be pathogenic to human beings, especially for children, whose principal food is often raw cows' milk.

Mohler and Traum, in studying the pathogenicity of this organism for man, examined the sera from forty-two human beings by complement-fixation and agglutination tests, using bacillus abortus as antigen. No positive results were obtained by these tests. The authors say: "Out of fifty-six tonsils and adenoids inoculated into guinea-pigs, tonsil No. 3 produced nodular areas in the liver, but cultures made from this organ remained sterile. Tonsils from case No.8, inoculated into two guinea-pigs, showed in one of them after three months distinct lesions of infection in the liver, spleen, and testicles, and bacillus abortus was obtained from the lesions."

Larsen and Sedgwick have made an extended study of human infection by this organism. They state: "If the bacillus abortus is pathogenic for human beings, as it is for guinea-pigs, and can be transmitted through the digestive tract, as is the case with cattle, we would expect infants and children to be the subjects most frequently infected. We have to date examined the blood of four hundred and twenty-five children by the complement-fixation method, and have found at least some support of the above expressed hypothesis. In these four hundred and twenty-five cases we found seventy-three positive and three hundred and fifty-two negative re­actions. In other words, the blood of seventeen per cent. contained anti­bodies against bacillus abortus." The same authors, in an attempt to answer the question whether these antibodies in the blood of children are the result of an active or a passive immunity, examined a number of samples of milk from cows that had recently aborted, but without being able to demonstrate the presence of bacillus abortus antibodies.

In their later investigations Sedgwick and Larsen found that new-born children who had not received cows' milk gave negative blood reactions in all of forty-two cases tested. One infant taken from the breast on the seventh day after birth and fed on cows' milk gave a positive reaction on the twenty­first day. Positive reaction was obtained in two children with enlarged spleens ,; children with many common diseases of childhood, including rickets, gave negative reactions.

Nicholl and Pratt also obtained positive agglutination reactions with blood sera of some children. In regard to their significance they say: "The presence of serum reactions is suggestive, but they again are not conclusive. failing the isolation of the bacillus from the lesions. That the ingestion of bacilli in large doses may be followed by the presence of antibodies in the blood has been demonstrated by several investigations .... "

Ramsey examined the blood of one hundred and sixteen children, of which fifty-eight were boys and fifty-eight were girls. Of these, seven cases gave a positive complement-fixation reaction-six boys and one girl.

That this reaction of the blood of children may indicate a passive immunity due to ingestion of milk is suggested by the work of Ehrlich and Wassermann, who found that young mice are capable of assimilating anti-

ABSTRACTS. 341

toxin through the intestinal canal and storing it in the blood, thus acquiring a certain degree of passive immunity.

The author claims to have shown in a previous paper that bacillus abortus antibodies are often' present in milk as it comes from the udder of an apparently normal cow, that these antibodies are often due to a local bacillus abortus infection, that one or more quarters may show the antibodies while the others are negative, and that the reaction may spread from quarter to quarter or gradually die out.

After giving the above resume of literature published on the subject, Cooledge describes a limited number of investi~ations carried out by him.

In these experiments the complement-fixation test and the agglutination test were used.

In the complement-fixation test rennet milk serum was used as antigen in the quantities: '04, '02, '0::l5 cc. Milk was considered positive only when there was fixation of the complement in the tube containing '04 CC'. of serum.

Agglutination tests were carried out by the addition of milk to a carbolised emulsion of bacIllus abortus in the proportion of I to 50, I to 100, I to 500,

and I to 1000.

In order to demonstrate the presence of bacillus abortus antibodies in the milk of apparently normal cows agglutination and complement-fixation tests were carried out with milk from nine cows. All gave positive agglutination reactions in dilutions up to I in 200. Complement-fixation was obtained in all but one of the cows with '02 cc. of antigen.

The fact that antibodies are often present in milk leads the author to suspect that the cases in which the appearance of antibodies in the blood of children has been looked upon as indicating infection by bacillus abortus are more probably due 'to an absorpti'on of antibodies from the milk in the intestine and a consequent passive immunity.

An examination was made of the blood-sera of fourteen persons (twelve men and two women) drinking raw milk, pasteurised milk, or no milk, and it was found that of the persons who had been taking raw milk or cream previous to the test, three (or 5 ° per cent. ) gave a reaction to the com­plement-fixation and agglutination tests. (Agglutinative power of 1 in 50,

partial in I in 50, and I in 100 respectively.) Of the four persons drinking pasteurised milk one gave a reaction to the complement-fixation test only (with '1 cc. of serum present).

One woman whose blood reacted to the test had been drinking milk which was found to contain bacillus abortus antibodies and had heen drawn from one quarter of a certain cow. One man whose serum gave a serum partial agglutination at I in JOO had been drinking about a pint of raw cream daily during the summer.

These results satisfied the author that the presence of antibodies in human sera is due to the ingestion of infected milk, and may indicate either active infection or merely a passive immunity due to the absorption of antibodies from the milk.

To determine whether bacillus abortus antibodies could be made to appear in the sera of adults by ingestion of infected milk a feeding experi­ment was arranged.

Milk for this experiment was obtained from six cows whose milk had a high bacillus abortus antibody content (agglutinating in dilutions from I in 100

up to I in 200), and caused bacillus abortus lesions and blood reactions when 5 cc. were inoculated into the abdominal cavity of guinea-pigs. Seven persons (six men and one woman) each drank daily over a period of eight weeks about a pint and a half of this raw milk. At the commencement of the experiment one man gave a partial agglutination result of 1 in 50, and

342 ABSTRACTS.

another of 1 in 100. The agglutinative powers shown during the test were 1 in 200 in the case of the man who previously gave a partial reacticn at I in 100; I in 100 in the case of the man who previously gave a reaction of I in 50; and I in 50 in the case of two men who gave negative reactions before the test. Complement-fixation tests corresponded approximately with the agglutination tests, except that in addition one man whose serum had not shown any complement-fixation previously now gave a partial result with 'r cc. Except in the case of the man who had shown a high agglutination (I in 200), all the human sera gave negative results when tested four weeks after drinking the milk containing antibodies.

There was thus an increased antibody content in the sera of five persons (or over 70 per cent.) during the test.

The author believes that these results indicate that the antibodies present in the human sera were due to passive immunity; if their presence had been due to infection of the individu31 by organisms present in the milk one would have expected a fairly high and lasting antibody content.

The following is the author's summary:-Summary.-We have no proof that bacterium abortus (Bang) is pathogenic

for human beings. It is possible to cause antibodies for bacterium abortus to appear in the

blood serum of adults by feeding them on milk which is naturally infected with bacterium abortus and which cont3ins the bacterium abortus antibodies.

Antibodies appearing as above apparently indicate a passive immunity due to the absorption in the large intestine of the antibodies present in an infected milk. (Cooledge, Tile Journal of Medical Research, July 19 16, Vol. XXXIV, pp. 458.)

SARCOSPORIDIA: ARE THEY ABERRANT FORMS OF CNIDOSPORIDIA OF INVERTEBRATES?

IN the year 1910 v. Ratz stated that sarcosporidia are very near to the nosematid::e. In an interesting paper Darling (1915) writes: "On account of the facility with which herbivora may obtain and ingest invertebrates infected with neosporidia, but more particularly flowers, leaves etc., or water contaminated with droppings of bees, moth larv::e, fly droppings, etc., or other material containing neosporidia spores, is it not possible that sarcosporidia may be slde·tracked varieties of some of the neosporidia of invertebrates which have invaded the musculature of a hospitable though by no means definitive host and, being unable to continue further their life.cycle, have escaped from a compromising and aberrant position?"

This opinion of Darling was supported by the experiments of Scott (1915), who concluded his paper with the following words: "All of the evidence favours the view that the sheep is not the definite host of sarcosporidia ten ella and, therefore, is in accord with Darling's suggestion that the muscle parasites of vertebrates are aberrant forms."

The author notes the following observations which seem to him to support the hypothesis that sarcosporidia are identical with cnidosporidia.

In 1896 Pian a, in a paper on the life·cycle of balbiania gigantea, states that in the cultures of this parasite on sterilised moist filter paper, moist earth, etc., at a temperature of 18° to 25° c., in twenty-five to sixty days the spores give bodies which develop more and more and present a nucleus and amccboid movements. The movements cease after some days and the amceba assumes the form of a cyst. Piana tried to infect a sheep per os with