SACCHAROMYCETACEAE IMPERFECTAE 329 



organisms in large aggregations. The organism penetrates from the meninges 

 along the perivascular sheaths of the vessels, forming flask-shaped cysts in 

 the upper layers of the cortex. In some instances the cyst formation is very 

 widespread (as in "soapsuds" cases), and subsidiary cysts are encountered. 

 In other instances the cysts remain more or less single. Deeper in the cortex 

 there are other cysts and granulomata that appear to have arisen through 

 embolism. Capillary emboli are occasionally found consisting of Cryptococcus 

 cells. The gray matter is particularly invaded, and small foci are often found 

 about the aqueduct and fourth ventricle. 



Of the other organs in the body, the lungs are most frequently invaded ; 

 very rarely the infection is generalized, even involving the skin. In these 

 cases a more pronounced inflammatory reaction is present in these other or- 

 gans, probably due to the normally greater amount of mesodermal tissue 

 present. The portal of entry is never the skin but is probably the respiratory 

 tract, either the lungs, the tonsils, or the sinuses. 



Most work on this disease has been based on the clinical and pathologic 

 sides and comparatively little on the organism. Stoddard & Cutler (1916), 

 under the guidance of Wolbach, first brought the pathologic picture to gen- 

 eral attention, but they did not attempt to isolate the organism from their 

 cases and based their experimental work on species of this genus isolated 

 more than a decade from lesions in the lung of a horse, assuming that an or- 

 ganism which produced a pathologic condition in experimental animals similar 

 to that they had found in man, must necessarily be the same species as that 

 which had produced the disease in man. Harrison, from a study of a number 

 of strains isolated from human cases, found somewhat different cultural and 

 biochemical characters with the same pathologic conditions. For want of a 

 name I have called his organism C. meningitidis. The work of Freeman. (1931) 

 indicates that there are probably three, or perhaps more, organisms which pro- 

 duced the same general pathologic condition, differing in minor respects, but 

 until there is more careful correlation of pathologic condition and cultural 

 characters, the nomenclature of this group must be unstable. Up to the pres- 

 ent only about half the pathologists who reported cases have described cul- 

 tures of the organism isolated, and not in a single case has it been adequately 

 described, while the only adequate description is not accompanied by case 

 histories or pathology. 



Key to Pathogfenic Species 



Colony white, grayish or yellowish. 



Pellicle thick, cells spherical or nearly so. 



On potato, colony white; from respiratory tract. C. Neveuxu. 



On potato, colony gray or drab or slightly yellowish; producing tumor-like lesions. 



C. neoformans. 

 On potato, colony yellowish brown; isolated from tumor. 



C. Plimmeri. 

 On potato, colony very dark brown; isolated from tumor. 



C. lithogenes. 



