CRYPTOCOCCUS TOKISHIGEI 



347 



then transplanted onto the same medium as Sabourand's medium. 

 The organism is easily cultured and develops rapidly. 



The most favorable temperature is 37 C. At this temperature 

 the colonies on Sabourand's agar have a yellow sandy appearance. 

 They are folded and have little white points. 



In the beginning the Cryptococcus enlarges and assumes a round 

 shape filled with oil droplets. It then buds giving mycelial tubes which 

 form lateral branches. 



On the secondary branches occur tertiary branches. At the end 

 of all of the filaments small buds form, the walls of which thicken 

 and the contents become filled with fat 

 globules. These detach themselves and 

 become external spores. These are prob- 

 ably the forms of the organism which 

 multiply under the shape of yeasts. In 

 culture, the spores form new mycelial 

 structures. The mycelium is also able 

 to form at the ends of the filaments a 

 small number of segments with chlamy- 



dospores having a very thick wall and Fig. 148-A^ - Cryptococcus^ To- 

 finely granular contents. In old cultures, 

 the units of the mycelium break off. 



At times the authors have noticed cells 

 with three or four elements resembling as- 

 cospores. This would tend to make the 

 yeast an Endomyces. The presence of ascospores does not seem to 

 be well established. As to the ascospores described by Tokishige, 1 

 Negre and Boquet have shown that they were simply granular bodies. 



Cultures of the yeast inoculated into a horse by scarification of 

 the epidermis and subcutaneous injection produced abscesses and 

 finally a clinical history of the natural disease. The Cryptococcus 

 appears in the lesions three to four weeks after inoculation. The 

 cells are at first isolated and have the shape of small oval units 

 with thin walls. Later they take on a double contour and appear 

 inside of the leucocytes. The serum from sick animals gives positive 

 reactions with cultures of the fungus. 



Boquet and Negre 2 have studied the variations taking place in 

 the development of Rivolta's Cryptococcus. They found that a mini- 

 mum temperature of 15-18 C. caused this parasite to take on a 

 mycelian structure. At the optimum temperature, 35-36 C., in liquid 



1 Tokishige. Ueber pathenogene Blastomyceten. Cent. Bakt. 19, 1896. 



2 Boquet, A., and Negre, L. Polymorphisme morphogenique du Cryptococcus 

 de Rivolta. Ann. Past. Inst. 33 (1919), 185. 



kishigei, Cultivated on Nutri- 

 tive Agar. 



a, Typical cells; b, c, Cells Containing 

 Granules Considered by Tokishige as 

 Ascospores; d. Free Granules Sup- 

 ' posed to have Sprung from the Cells; 

 e, f, Transformation of the Cells 

 into Filaments (after Tokishige). 



