542 
morpholog}’ and virulence. In their work they give a history of in- 
vestigations similar to their own which strengthens the evidence for 
the conclusion that v*e can find nothing in the morphology and viru- 
lence of tubercle bacilli to encourage us to undervalue the importance 
of those from bovine sources for public health. 
Fibiger and Jensen.® who likewise obtained typical bovine bacilli, 
virulent for cattle, from human lesions, recall that the imperial Ger- 
man health office examined 39 cases of primary tuberculosis of the 
human intestines and mesenteric glands and found that 13 among 
them were caused by bacilli of the boffine dype. Later investigations 
made by Fibiger and Jensen are summed up as follows: Though bo- 
Aune types of tubercle bacilli are more commonly isolated from bovine 
lesions and human types from human lesions, there are cultures that 
^ must be considered as transition forms, as they have some of the 
characteristics of boAune and others of the human type.^ 
Gorter,® after a careful study of tubercle bacilli from hiunan and 
boA’ine lesions, found T among 21 cultures from hiunan sputum which 
he regards as identical with the transition forms between human and 
bovine bacilli which he says are described by Kabinowitsch. He con- 
cludes that human and bovine bacilli are not different varieties, and ' 
that the conA’ersion of the one type into the other actually occurs. 
Sargo and Suess^^ showed that mutations occur in human tubercle 
bacilli and other types, which sj^eak against grouping tubercle bacilli 
from animals of different species as sj^ecial A^arieties. 
Von Behring,® who ranks as one of the most widely recognized 
authorities on tuberculosis, found cultures of tubercle bacilli isolated 
from man of low Afirulence for cattle, and others of higher Aurulence 
for them than many cultures of boAune origin. He declares himself 
as opposed to the AueAv that bovine tubercle bacilli may be harmless 
for man, and calls attention to the fact that they generally haA^e a 
higher grade of Aurulence than human bacilli, and are therefore to be 
regarded as more dangerous. 
The British royal commission on human and animal tuberculosis ^ 
concluded from its iiiA^estigations that cow's milk containing bovine 
tubercle bacilli is clearly a cause of tuberculosis, and of fatal tuber- 
culosis in man, and that a A^ery large portion of tuberculosis con- 
tracted by ingestion is due to tubercle bacilli of boAune origin. 
° Berliner Klinische Woclienschrift, Nos. 4 and 5, 1907. 
® Presented at the joint session of Sections I and VII of the International 
Congress on Tuberculosis, Washington, D. C., 1908. 
® Zeitschrift fiir Tnberkulose, A’ol. XI, Xo. 3, 1907. Also Inter. Centralb. fiir 
die ges. Tuber. Fors., A^ol. II, Xo. 1, 1907. 
^ Centralb. fiir Bacteriologie, etc., Vol. XLIII, Part I, pp. 422-529. 
® Berliner Tierarz. Wochens., Xo. 47. 1902. 
f Jour. Boyal Institute of Public Health, Vol. XV, Xo. 3, 1907. 
