420 M. ARMAND BUFFER. 



tity of the virus, in the shape of a dried powder, has been 

 introduced under the skin, a small hard swelling is formed at 

 the seat of inoculation^ which crepitates on pressure as if its 

 contents consisted of gas and fluid. The tumour increases in 

 size, and soon becomes harder and more resistent. The parts 

 surrounding it are then considerably thickened, the walls of 

 the abdomen, for instance, feeling twice as thick as natural. 

 After twenty-four hours or so the animal shows evident signs 

 of a general illness ; it refuses food, does not run away when 

 touched, gets more and more drowsy, and generally dies just 

 within forty-eight hours after the inoculation. 



On examining the tissues of the spot where the inoculation 

 has been made, the remains of the powder containing the virus 

 are found lying in a kind of cavity full of almost clear fluid. 

 The walls of this cavity are lined by a thin, greyish, and 

 fibrinous layer. The muscles surrounding the cavity are 

 highly cedematous, so that on cutting through them a large 

 quantity (10 c.c. to 20 c.c. or more) of clear, transparent, 

 reddish fluid may be collected. 



If twelve hours after the inoculation a sharp capillary pipette 

 be introduced into the centre of the tumour already formed, 

 and a little of the transparent fluid be carefully drawn ofi" and 

 examined under the microscope, an enormous number of bacilli 

 will be found moving about in the liquid. Here and there a 

 leucocyte is seen. As a rule, the wandering cells met with at 

 this stage are empty, but occasionally one holds two, three, or 

 more bacilli in its interior. 



In cover-glass preparations stained in an alkaline solution 

 of methyl-blue, or better, gentian-violet, the bacilli floating in 

 the liquid are, to all appearances, perfectly normal, and, 

 according to the reagent used, stain of a lovely dark blue or 

 purple colour. Most of the bacilli contained in the cells stain 

 normally, but here and there an intercellular bacillus shows 

 signs of degeneration. 



A drop of the liquid from the tumour withdrawn and ex- 

 amined at the end of forty-eight hours, or immediately after 

 the animal's death, contains an enormous number of free 



