VETERINAKY MEDICINE. 185 



The pathogenic effects of bovine viruses, A. S. Griffith {Roy. Com. Tuber- 

 culosis, Second Jiitcrhn Rpt., 1 {1901), pt. 2, App., pp. Ill, pis. 17). — Since 

 1903, the author has carried on continuous observations in the study of the 

 biology and patliogenic relations of tubercle bacilli of bovine origin. An elab- 

 orate system of technique was devised for the estimation of the number of 

 tubercle bacilli present in cultures. In arriving at an estimate of average re- 

 sults along this line, 1,39 counts were made. The calculation is admittedly 

 imperfect but indicates clearly that the great majority of culture inoculations 

 are ricber in tubercle bacilli than inoculations with even the largest doses of 

 tissue emulsions. It is estimated that each cubic millimeter of the culture 

 contains from 4,000,000,000 to 5,000,000,000 tubercle bacilli. 



In the experimental work carried on by the author, bovine tubercle I)acilli 

 were inoculated into cattle, goats, pigs, apes, monkeys, dogs, cats, rabbits,, 

 guinea pigs, etc. Inoculation was accomplished by the intravenous, intraper- 

 itoneal, intramammary, and subcutaneous methods and also by feeding. The 

 purpose of the feeding experiments with bovine tubercle bacilli was to ascertain 

 the relative susceptibility of different species of animals to this mode of infec- 

 tion and to study the distribution of tuberculosis lesions thus produced. In 

 these experiments, .318 animals belonging to 15 distinct species were used. The 

 majority of the animals were fed single doses of tubercle bacilli either in the 

 form of a culture or in tuberculous milk. Some of the experimental animals 

 were fed at intervals for varying periods with tuberculous milk. 



It appears that in cases where animals are fed a single dose of tubercle 

 bacilli there may be many individual factors which greatly influence the result. 

 For example a catarrh of the mucous membrane of the intestines may protect 

 the animal from infection by liastening the expulsion of the intestinal contents. 

 Tubercle bacilli are readily absorbed from the alimentary canal of pigs but 

 much less rapidly in the case of guinea pigs. Individual susceptibility exer- 

 cises an important influence on the result. The chimpanzee, baboon, rhesus 

 monkey, lemur, rabbit, and guinea pig are highly susceptible to the action of 

 bovine tubercle bacilli, and infection from however small a dose is almost inva- 

 riably followed by progressive tuberculosis. In the pig, goat, calf, cat, and dog, 

 on the other hand, with the possible exception of the young pig, tuberculosis 

 produced by feeding may be limited to the glands along the alimentary tract, 

 particularly if the dose of tubercle bacilli is small. In young pigs tuberculosis 

 is usually of a progressive type. Adult swine are, however, somewhat more 

 resistant. 



The infection of the organism with general tuberculosis of the lungs from 

 the subcutaneous connective tissue, blood, and alimentary tract, A. D. 

 Pawlowsky {Ztschr. Tuberkulose, 12 {190S), Xo. 1, pp. 31-'i5). — The author's 

 experiments have been carried on since 1903 and have consisted largely in feed- 

 ing guinea pigs human tubercle bacilli in milk. The guinea pigs were then killed 

 after a lapse of 1 to 3 or more weeks and carefully examined to determine the 

 extent and distribution of tuberculous infection. The experiments show that 

 tuberculosis in the early stages is confined almost entirely to the lymphatic 

 glands while the stomach and intestines are unaffected. The tubercle bacilli 

 pass through the walls of the alimentary tract without causing any lesions in it 

 and remain for some time in the mesenteric glands. From these points they may 

 be carried through the lymphatic system and after a period of from 6 to 8 weeks 

 may appear in the lungs. 



Morphological variation in the tubercle bacillus, S. Arloing ( Compt. Rend. 

 Acad. Sci. [Parisl, 11,6 {1908), No. 3, pp. 100-10',, figs. 3).— Under artificial con- 

 ditions obtained by modification of the nutrient media, temperature, etc., it was 



