METHOD OF EXAMINATION. 155 



in a flocculent manner, leaving the fluid clear ; the second variety 

 produces a membranous top growth, with irregular masses of 

 round cells and mycelial tufts at the bottom or adhering to the 

 sides of the tube, the membrane so formed may through increas- 

 ing weight sink and be replaced by a new formation ; the third 

 type forms no top growth, nor clouds the medium, but grows as 

 small, discrete woolly tufts at the bottom. On agar or gelatin 

 plates the colonies of the first type are round, moist, glossy, 

 white, opaque, and elevated, and under the low power of the 

 microscope are found to be coarsely granular, and individual cells 

 can be seen at their peripheries. The second type shows round- 

 ish colonies having the characters described upon agar slants ; 

 microscopically the colonies are made up of branching segmented 

 mycelium radiating outwards from the centre of the colony. In 

 the third type the colonies have the general characters of the 

 slant agar growth, and under the microscope appear to be made 

 Tip of long radiating, branching segmented mycelium, which here 

 and there shows occasional budding. 



Fermentation of glucose and maltose with the production of 

 alcohol, acetic acid, and carbon dioxide takes place with some 

 varieties, whilst in others no fermentation occurs at all. Cane 

 sugar and lactose are not fermented by any variety. 



Litmus milk is rendered usually neutral or alkaline by the 

 growth, whilst acidity and coagulation of the casein is very rare. 



Gelatin in some instances is liquefied slowly. 



Pathogenic Properties. — Towards the lower animals patho- 

 genic properties vary very much with the culture, recently 

 isolated cultures as a rule proving more virulent than older 

 ones. Mice, guinea-pigs, and dogs are most susceptible, suc- 

 cumbing often to subcutaneous and intraperitoneal inoculations, 

 whilst the white rat, rabbit, sheep, and horse are more refrac- 

 tory; in all, the lesions may be localized in the form of abscesses, 

 or general infection may ensue where subcutaneous inoculation 

 is practised. 



Methods of Examination and Isolation. — ■ Pus from subcu- 

 taneous abscesses, or scrapings made with a curette from the 

 inflamed indurated skin growth are to be placed on a slide and 

 thoroughly macerated in a thirty per cent solution of sodium 

 hydrate, which dissolves the pus or tissue cells and permits of 

 the more ready identification of the blastomycetes, which are 



