SYSTEMATIC AND DESCRIPTIVE. 287 



cultivation are treated as follows : The inocu- 

 lated surface containing the creamy cultivation 

 is sliced off in a thin layer, and is mashed up 

 with distilled water in a glass capsule. Sterilised 

 silk-thread is cut up into lengths of about a quarter 

 of an inch, and allowed to soak in the paste for 

 some hours, under a bell-glass. The threads are 

 then picked out with a pair of forceps, and laid upon 

 a sterilised glass plate, covered with a bell-glass, 

 and allowed to dry. From the plate, when perfectly 

 dry, they are transferred to a small test-tube, which 

 can be plugged with cotton-wool, or sealed in the 

 Bunsen burner. 



Examination in the tissues. The organs must be 

 hardened in absolute alcohol, cut and stained, 

 (pp. 54, 291). The method of Gram is the most 

 instructive, and eosin a very satisfactory contrast 

 stain. The capillaries all over the 'body, lungs, 

 liver, kidney, spleen, skin, mucous membrane, etc., 

 will be found to contain bacilli. In some cases the 

 bacilli are so numerous (e.g., in the capillaries of 

 the kidney, Plate XVI., Fig. 2), that examination 

 with a low power gives the appearance of an 

 injected specimen. 



Inoculation of animals. A thread containingspores, 

 a drop of blood from an infected animal, or a 

 minute portion of a cultivation, introduced under 

 the skin of a mouse or guinea-pig, causes its death, 

 as a rule, in from twenty-four to forty- eight hours. 

 Sheep fed upon potatoes which have been the 



