ABSTRACTS. 12 5

acquired beginning to deeline after the third month following the im­munising injection, and that attenuated bovine strains have a considerable immunising value against virulent strains of both bovine and swine origin.

A similar method of immunising pregnant cattle and swine might profitably be tried.

Agglutinatz"on Reactions and thez'r Significance.

Animals having an agglutination reaction not higher than one-hundredth a month after all exposure to infection has ceased have never heen found to harbour abortion organisms in their body.

A large proportion of cows that react in a dilution of one-hundredth or more have infected udders.

This is of importance in being able to say ",hether an animal is safe or dangerous so far as the dissemination of abortion organisms is concerned. Caution must be exercised, as a low reaction may be the beginning of a high reaction.

The above standard does not apply to swine, as they may be carriers of the organism and give an agglutination reaction to a dilution no high er than one-fiftieth.

There is urgency for standardisation of the agglutination and complement fixation tests before results obtained by different workers can be comparable. ("Journ. of the Amer. Vet. Med. Assoc.," 1925, Vol. LXVI., pp. 550-56I.)

THE BACTERIOLOGY OF THE INTESTINAL TRACT OF YOUNG CALVES WITH SPECIAL REFERENCE TO THE EARLY DIARRHCEA (" SCOURS.")

Ey THEOBALD SMITH and MARION L ORCUTT.

THE studies describfd by the authors were made to obtain some infor­mation concerning the common occurrence of diarrhcea or cholera of very young calves wh ich frequently terminates in death during the first week of life. As the trend of these studies has, in a way, heen shaped by the results obtained recently in experiments with colostrum, abrief resurne of these is given. It was shown that new-born calves fed on milk in place of colostrum, with few exceptions, succumbed within a few days to a generalised infection with B. coli. Among the calves which received colostrum there were a few that became manifestly ill, probably as a result of receiving not enough colostrum. These partly recovered and devoloped in the second week swellings of one or more joints, chiefly the tarsal. When such animals were killed, organs and joints were found to contain a small number of bacteria, chiefly E. coli. These were evidently held in check and gradually destroyed by the partial immunity furnished by the colostrum. This latent or partly suppressed microbism was also responsible for a peculiar nephritis leading to the well-known spotted kidney. The tissues and organs of calves sufficiently protected by colostrum or cow serum were found sterile, except occasionally the liver. It is suggested that the elose relation between the liver and the digestive tract, through the portal vein, serves to account for this occasional escape of B. coli.

The material used in the author's studies consisted of five groups of calves, all from the same herd :-

116 ABSTRACTS.

(a) An early normal group killed within twenty-four to seventy-two hours of birth.

(b) A group about two days old evidently in an early stage of scours, but as yet without definite symptoms.

(c) Calves having diarrh~a and symptoms of toxxmia. (d) Calves examined immediately after natural death from scours, or

within twelve hours after the bodies had been chilIed with a stream of cold water and refrigerated.

(e) Normal calves up to three or more weeks of age. Most emphasis was placed on calves killed and promptly examined. The

abdomen was opened and the stomachs ligated and removed. The intestines were then rapidly cut from the mesenteries, and 6-inch portions, 10 to 12 feet apart, beginning with the duodenum, removed and examined immediately or placed in a refrigerator. The seroUS surface of such segments was seared, the wall incised, and a loop introduced to remove material for microscopic examination, plating, etc. In some cases a small amount of bouillon was introduced to make a suspension of the contents. The condition of the mucosa at the different levels of the small intestine was ascertained by snipping off minute bits which brought away a small number of villi and examining these fresh. The presence of bacteria determined by this ex­amination was confirmed by dried films of contents and scrapings stained by Gram's method. At the same time plain and blood-agar plate cultures were made with contents or scrapings at the five or six different levels of the small intestine, and with contents of the fourth stornach and the cxcum.

It is impossible to say what the subsequent course of a calf, normal when killed within the first twenty-four or forty-eight hours, would have been. After the third day, however, certain changes have taken place. The colostrum has given way to the ordinary milk diet. A reducing substance present in the urine at birth has disappeared. The peculiar "dropsical" epithelium of the lower small intestine found in many cases during the three first days is not seen thereafter. Finally, the urine is now free from protein, or all but traces of it, provided a nephritis due to B. coli. is not under way.

Petechix and petechial hxmorrhages alm ost regularly present in the mucosa of the fourth stornach at birth, and presumably due to mechanical causes du ring parturition, may playa part in the decline of the calf, even causing its death when combined with scours.

Omphalitis following infection of the umbilical stump, with progression of the inflammation along the umbilical vein into the liver, was very rare in the cases sludied, so that there was little to complicate the intestinal disease.

The invasion of the digestive tract by bacteria after birth has been the subject of a number of papers in the past. It was possible in this investiga­tion to examine the intestinal tract at different hours after birth in calves prematurely born and without food in the stomachs. In general the inva­sion is by the mouth rather than per rectum. Bacteria penetrate as far as the cxcum within twelve hours in calves not sucking. To this point the meconium is liquid and favourable to a rapid diffusion of bacteria; below this it is consistent and much drier. Cultures made from various segments of the digestive tract in premature but living calves infected with B. abortus have contained miscellaneous bacteria until the rectum was reached. The contents at this point still yielded pure cultures of B. abortus.

Group A.-Data upon young calves when free from symptoms of scours or diarrh~a have been gathered from cases killed from time to time since 1917 for the preparation of culture media. The results were quite uniform and indicated a fairly stable flora. Although a number of different species

ABSTRACTS. 12 7

may succeed in reaching the small intestine, they are not in evidence because so few in numbers. The bacteria that are significant are those that are capable of multiplying and appearing in sufficient numbers to be detected in fresh and stained films. Two species occupy the field in the normal calf, in the fourth stornach Bacillus acidophilus and Gram-positive cocci which may be called enterococei; and the same speeies are found throughout the small intestine. In the ileum B. coli appears in small numbers in plates, rarely abundant enough to be recognised in films. In general the bacterial eontent of the fourth stornach, aside from B. acido­philus, is more varied than that of the small intestine, probably because it depends on the condition of the ingested food. In the duodenum it may be higher than in the next lower levels, where it falls to aminimum. It gradually increases again towards the ileo-ereeal valve. No approximate figures are available beeause the stage of intestinal digestion, or, in other words, the partieular level where the ehyme happens to be when the animal is killed, governs the number. The ehyme earries with it living and dead baeteria, whereas the empty intestine is relatively sterile.

Grou} B.-In a eertain nu mb er of ealves during the second day, when normal eonditions still prevail, B. eoli may be found in fairly large numbers in the ileum, and in eertain eases in one or more segments higher up.

Grou} C.-When the freees had become fluid the multiplieation of B. eoli in the lower segments of the small intestine was pronouneed in all animals examined. Several cases are quoted to confirm this, and in one ease there is evidenee from the protein output in the urine that the calf obtained a large amount of eolostrum without resisting B. coli invasion of the small intestine. Calves killed in the course of scours after the third day present the same intestinal flora as those killed when one or two days old.

Grou} D.-Calves dying of scours, when promptly chilIed and re­frigerated if the organs cannot be removed immediately, show the same conditions as in those killed. The small intestines are flooded with B. coli. In part this is only the result of post-mortem multiplication, as it has been observed that multiplieation goes on at a very rapid pace in the hours before death.

Grou} E. - Calves which had maintained normal conditions of the intestines were examined from time to time with reference to the intestinal flora. In all eases B. eoli was either absent in plates or else present in very small numbers.

DrSCUSSION.

B. eoli is probably present in all levels of the sm all intestine in the normal animal, but frequently in such small numbers that only incubation of contents in bouillon overnight brings it to light. In all eases of intestinal disturbance B. coli is present in the lower small intestine in larger num bers than in health, and as the disease progresses the numbers of living baeiIJi not only increase locally but the infeetion spreads towards the duodenum. The action of B. coli in bringing about the loeal hyperremia and flux and tbe general intoxieation is probably a result of the absorption of toxins produced and set free during multiplieation.

Are the multiplieation and eonsequent intoxieation due to an inadequate functioning of the mueosa and assoeiated glands, or to an unusual virulence of the invading B. eoli? The authors answer this question by stating that it must be inferred that the genesis of seours as a herd disease is the result of both inadequate digestive funetions and increasing virulence of B. eoli.

ABSTRACTS.

These two factors reciprocally favour each other in the sense that the depression of normal functions favours multiplication and rapid passages from case to case, and consequent rise in virulence, where animals are numerous. Among the conditions leading to an inhibition of normal pro­tective functions a failure of the peptic stomach alld its secretions in the early hours of li fe may give B. coli the necessary opportunity, while another factor may be the over-distension of the fourth stomach with colostral milk. The over-distension may be due to a delayed feeding which stimulates the calf to over-feed. This delay mayaiso be significant in permitting B. coli to get a foot-hold in the small intestine in spite of the large but delayed dose of colostrum. Attention is also called to the large amount of coagulable protein in the contents of the ileum. This passing into the large intestine becomes the white scours.

The authors state that the relation of virulence of B. coli to scours is still under investigation and only certain data can be cited now. In the early cases studied the dominant race of B. co li was saccharolytic and motile. Later this type was supplanted by one which is non-motile and fails to act upon saccharose. The author infers that scour is associated with the multiplication of special races of B. coli and that such races are developed and maintained in large herds. Each large herd, through the presence of calves below par at birth, may develop and maintain its own type of scours organism, which, however, is not virulent enough to make any headway in naturally strong calves properly cared for as regards food and housing. It is stated that a sm all outbreak in four calves, from which a paratyphoid bacillus was isolated, was encountered, but the nature of the disease and the lesions observed were different.

CONCLUSIONS.

New-born calves recelvmg no colostrum, or else receiving it after some delay, may die of B. coli septicremia, of which scours is a local manifestation.

Calves receiving an insufficiently protective dose of colostrum may become victims of various bacterial diseases, such as arthritis, nephritis, omphalitis, and possibly pneumonia.

Calves receiving a sufficient dose of colostrum may still develop ·scours of various degrees of severity, due to the local multiplication of various types of B. coli in the sm all intestine.

There exists in the young calf a delicate balance between certain strains of B. coli and the mucous membrane and digestive ferments, which, upset in favour of B. coli, produces scours. The necessary conditions for such attacks are in part inherited defects of the digestive tract, both morpho­logical and functional, and special types of B. coli,resident in the herd.

The immediate indications are a great increase in the number of B. coli in the lowest third of the small intestine with a spreading of the invasion towards the duodenum as the disease gains headway. Under these con­ditions a general intoxication results. The bacilli form layers or films attached to the top plates of the epithelial cells, but at this time no morphological changes in the cells are recognisable. (Journ. of Exp. Med., 1925, Vol. XLI., p. 89.)