702 THE PARASITIC YEASTS 



SECTION I. THE GENUS ENDOMYCES. 

 Endomyces albicans (Vuillemin). 



Synonyms. Saccharomyces albicans Audry : Oidium albicans Robin : 

 Syringospora robini Quinquaud. 



The parasite of thrush was discovered by Ch. Robin who gave to it the 

 name Oidium albicans. Audry examined the organism and classified it with 

 the yeasts. Guiart relying on the fact that both filaments and yeast-forms 

 can be seen places it among the Oididse. [Vuillemin, however, demonstrated 

 the formation of true spores within the filaments.] 



Endomyces albicans is present in the air and is constantly passing into the 

 respiratory passages, but is only able to live on the mucous membrane of the 

 mouth when the salivary secretion is altered by some pre-existing disease. Thrush 

 may infect the mucous membrane of the oesophagus and stomach, and occasionally 

 also the mucous lining of the anus and vulva. Under certain exceptional conditions 

 the parasite enters the blood-stream and causes a generalized infection (Virchow, 

 etc.). Cases of thrush have been reported in colts and calves and also, but rarely, 

 in birds (Eberth, Martin). 



1. Experimental inoculation. Endomyces albicans produces merely a local 

 lesion when inoculated into the anterior chamber of the eye, into the peri- 

 toneal cavity, or beneath the skin of a rabbit. Inoculation of a pure culture 

 of the fungus into the ear- vein of a rabbit may lead to a generalized mycosis 

 with metastases in the internal organs, and may terminate fatally. 



In guinea-pigs, intra-peritoneal inoculation produces peritonitis with the 

 formation of false membranes. Intra-pleural inoculation is followed by an 

 effusion of fluid into the pleural cavity and the parasite may subsequently 

 become generalized. 



2. Morphology. Microscopical appearance. 1 .. In the tissues. To demon- 

 strate the parasite in cases of thrush, remove a portion of one of the 

 characteristic whitish curdlike patches seen in the mouth, break it up in a 

 little water on a slide, treat for a few seconds with a strong solution of 

 Gram's liquid (p. 209) and cover with a cover-glass : when the preparation 

 is examined under the microscope the yeasts will be seen stained brown by 

 the iodine. The material may instead be broken up in a drop of acetic acid 

 which clears the epithelial cells and renders the parasite more readily visible. 

 Dried films should be stained with an aqueous solution of a basic aniline dye, 

 which will stain the protoplasm of the parasitic cells. 



The white spots of thrush consist of the parasite mixed with epithelial cells. 

 The Endomyces has the appearance of long tubular septate and entangled 

 filaments mixed up with ovoid or rounded corpuscles having a large nucleolus 

 (the mycelium and spores of older writers). 



2. In cultures. The appearance of Endomyces albicans depends upon the 

 nature of the medium on which it is growing, being absolutely different on 

 different media. [Generally speaking, it may be stated that the more solid 

 the medium on which it is grown, the greater the tendency to spore forma- 

 tion : the more liquid the medium, the greater the tendency to the formation 

 of filaments (Wills).] In broth cultures, forms similar to those just described 

 are found, namely long entangled filaments mixed up with numerous oval 

 cells. In wine, long filaments alone are seen, no oval cells. In cultures on 

 solid media only oval round or irregular cells occur, arranged singly or in 

 irregular groups, each cell being surrounded by a refractile membrane which 

 does not take the basic dyes : some of the cells will be seen to be actively 

 budding. In Njegeli's medium the growth assumes peculiar characters": 

 microscopical examination shows rows or chains of oval cells on the ends of 



