28 THE GROUSE DISEASE chap. 



(2.) Character of the microbe in the fresh state : — 

 The microscopic examination of the microbe in 

 the living or fresh condition, i.e. in a drop of sahne 

 solution, or serum, or broth, shows it to be a spheri- 

 cal, or more generally an oval corpuscle, occasion- 

 ally more distinctly rod-shaped or cylindrical, with 

 rounded ends. The microbes occur either single or, 

 more commonly, double, i.e. as dumb-bells (Fig. 

 9). The great majority are without any movement 

 of their own, showing only the oscillating move- 

 ment that all granules suspended in a fluid show, 

 namely, the Brownian molecular movement. But 

 occasionally one or the other shows active locomo- 

 tion, either spinning round and round, or darting, 

 under oscillation of its body, through the field of 

 the microscope. Such actively motile individuals 

 are to be seen fairly frequently in a fresh prepara- 

 tion made of a recent colony from a gelatine plate, 

 or from a recent gelatine tube-culture, or from Agar 

 culture, from the fresh lung -tissue or from the liver. 

 By means of the platinum wire a particle of the 

 culture or of the tissue is suspended or distributed in 

 sterile salt-solution — or better, in broth — and examined 

 either in the " suspended drop," i.e. in the hollow 

 glass slide, or simply mounted on an ordinary glass 

 slide. The number of non-motile bacteria is always, 

 under the most favourable conditions, greatly in 



