TUBERCULOSIS 79 



The British Royal Commission in its final report of July, 1911, considered three 

 types of T. B. 



I. The bovine type belonging to the natural tuberculosis of cattle. 

 II. The human type. The type more generally found in man. 

 III. The avian type, belonging to natural tuberculosis of fowls. 



The bovine type grows slowly on serum and at the end of two to three weeks 

 shows only a thin grayish uniform growth which is not wrinkled and not pigmented. 

 The human type grows more rapidly and tends to become wrinkled and pigmented. 

 Subcutaneous inoculation of 50 mg. of culture into the neck of calves produced 

 generalized tuberculosis. A similar injection of human T. B. does not cause general- 

 ized tuberculosis but only an encapsulated local lesion. 



Intravenous injection of o.oi to o.i mg. of bovine T. B. into rabbits causes general 

 miliary tuberculosis and death within five weeks. With human T. B. in doses of 

 o.i to i.o mg., similarly injected, the majority of rabbits live for three months. 



Subcutaneous injection of 10 mg. bovine T. B. causes death in 28 to 101 days. 

 Similar injection of human T. B. in doses up to 100 mg. did not kill the rabbits after 

 periods of from 94 to 725 days. The duration of life in injected guinea-pigs is longer 

 with human than with bovine T. B. 



Subcutaneous injections of bovine T. B. into cats produces generalized tubercu- 

 losis while the cat is resistant to human T. B. thus given. 



Recent statistics (Beitzke) show tuberculous lesions in 58% of 

 adults at autopsy Naegli's figures were about 90%. 



It is a question whether the avian type is absolutely distinct; many 

 experiments having indicated the impossibility of infecting fowls 

 with human T. B. Nocard, by inserting collodion sacs containing 

 bouillon suspensions of human T. B., claims to have changed these to 

 the avian type. The avian type grows at 43 C. fairly luxuriantly r as a 

 moist, more or less spreading culture. It grows much better on gly- 

 cerinated agar than on serum. Morphologically they are like the 

 human type, but show less tendency to form compact masses. Very 

 pleomorphic. Have been reported from sputum of man (doubtful). 



Fowls become infected by intravenous or subcutaneous injection or as the result 

 of feeding. After feeding the lesions are chiefly of the alimentary tract; after in- 

 jections, of spleen, liver and lungs. Avian T. B. is more virulent for rabbits than 

 human T. B. but less so than bovine T. B. The mouse is the only animal besides the 

 rabbit in which avian T. B. can cause a generalized tuberculosis. The conclusions 

 are that there is no danger to man from avian T. B. With the bovine type it is 

 quite different as nearly one-half of the deaths in young children from abdominal 

 tuberculosis were due to bovine T. B. and to that type alone. Not only in children, 

 but in adolescents suffering from cervical gland tuberculosis, a large proportion were 

 caused by bovine types. The bovine type is also an important factor in lupus. 



There is also a fish tuberculosis. This organism grows much more 



