SACCHAROMYCES TUMEFACIENS 



705 



red- violet : the refractile granules are unstained. The fungus stains by 

 Gram's method. 



(6) In human and animal tissues, the parasite is much larger and occurs 

 as spheres 16-20//. in diameter each with a wall about 0'5/x thick and surrounded 

 by an hyaline capsule from 8-10/* thick : ovoid forms and cells in an active 

 stage of budding are also seen. The bud separates and the mother and 

 daughter cells are then contained within the same capsule : the young buds 

 are filled with grains of chromatin. 



Sections. For sections, Curtis recommends the following technique : 



1. Stain for a few minutes in Orth's carmine. 



2. Stain for 10 minutes in the following solution : 



Saturated solution of methyl-violet 6B in absolute alcohol, 

 1 in 10,000 aqueous solution of caustic potash, 



3. Decolourize for 1 minute in a pyrogallol solution : 



Pyrogallol, 



Distilled water, 



1 c.c. 

 9 c.c. 



1 gram. 

 100 c.c. 



4. Dehydrate. Mount in balsam. 



3. Cultural characteristics. S. tumefaciens is an aerobic organism. 

 Growth takes place at ordinary temperatures but is best at 37 C. and on 

 neutral or slightly acid media. 



Agar. When the culture is sown with material from an animal tissue, 

 white opaque punctiform colonies appear after 2 or 3 days which ultimately 

 coalesce but never form an uniform streak. After sub-cultivating several 

 times on agar, growth is more rapid and more abundant, and a shiny thick 

 creamy growth is obtained from which sub-cultures can be sown as long as 

 6 months afterwards. 



Gelatin. Along the line of the stab, a small white discontinuous track of 

 growth appears composed of punctiform colonies which are more numerous 

 near the surface. The medium is never liquefied. 



Broth. The growth is very poor and consists of small white flocculi which 

 fall to the bottom of the tube leaving the medium quite clear. 



Beer-wort. The growth is more copious than on broth which is also the 

 case with all media which are acid to the extent of ! 3-0'5 of sulphuric acid 

 per litre. 



Potato. At 37 C. in 48 hours a white dry-looking streak appears which 

 subsequently becomes brown. Growth 

 is more abundant on glycerin-potato. 



On serum. No growth. 



2. Other species of saccharomyces. 



(a) Saccharomyces anginse. Achalme 

 and Troisier have recorded a case of sore 

 throat clinically resembling thrush, but 

 due to a yeast consisting of ovoid globules 

 showing more or less large buds. 



5. angince grows easily on ordinary 

 media. On solid media the growth is 

 thick copious and pinkish-grey in colour. 

 Microscopical examination of cultures 

 shows forms identical with those found 

 in the tissues, and occasionally [in 



cultures grown on alkaline peptone gelatin] asci each containing four 

 ascospores. 



2Y 



FIG. 339. Saccharomyces angince. (After 

 Troisier and Achalme.) 



