THE COMMUNICABLE DISEASES 511 
fibrosis is not so common as in the bovine tubercle. I 
have attempted to study the histological anatomy of each 
of the zoological orders, but it has not resulted in any 
profitable discovery. It is, however, possible to contrast 
the type commonly found in monkeys with that character- 
istic for man and the ungulates and also to emphasize the 
construction of the avian tubercle that it may be dis- 
tinguished from mammalian tuberculosis and from 
avian mycosis. 
The tubercle of the Primates is a loosely constructed 
affair lacking the fibrous mixture of the bovine and the 
close cellular packing of the human form. Studied from 
the periphery to the centre, there will be found very little 
fibrocellular reaction in the immediately surrounding 
organ, while the mantle of round cells, rather prominent 
in the human tubercle, is often quite inconspicuous. The 
principal cellular component of the miliary granuloma is 
the large pale endo- or epithelioid cell, which is abundant, 
loosely arranged and without apparent purpose. In the 
centre is an irregular necrosis usually retaining some 
chromatic matter, probably the remains of recently 
destroyed nuclei, but this caseous midpoint does not 
assume the dense acid staining common for many milia. 
Giant cells of the Langhan's or foreign body type are 
often entirely missing, and when present are scanty. 
There may be large cells, resembling the aforementioned 
epithelioid cells, with two or even three large palely stain- 
ing nuclei, but these latter are arranged irregularly and 
not like the spokes of a wheel near the cell wall. 
This picture suggests a rapidly growing inflammatory 
mass and indeed this is the type that tuberculosis follows 
in monkeys. In a few cases gross evidence of fibrosis in 
the serous surfaces and in the lungs has been observed, 
but they are too rare to permit one to think that con- 
nective tissue activity is an important part of the reaction 
of this beast to the disease. 
