YEAST-LIKE FUNGI OF HUMAN INTESTINAL TRACT 29 



myces hominis, Torula humicola, Blastomyces dermatitidis, Oidium albicans, 

 Torula rubra, Monilia X of Ashford, Simon's ('16), Binot's ('03), Curtis ('95), 

 and Foulerton's ('99) pathogenic yeasts were those most carefully studied. The 

 nonpathogenic determined yeasts used are given in Table 2. 



The pathogenic yeasts most nearly resembling the intestinal fungi isolated 

 were Oidium albicans,* Monilia X of Ashford, and Simon's species. Ashford's 

 Monilia has many characters in common with Oidiunr albicans, and consid- 

 ering the wide variation in cultural and biochemical characters which this 

 species apparently undergoes it is questionable whether the fungus associated 

 with sprue is a distinct species. Ashford ('ISc) writes that his organism is 

 not Monilia albicans, but does not state the grounds on which he bases his 

 assertion. Culture 2.5, isolated from a case diagnosed as sprue, is the same 

 as Ashford's Monilia X. This was the only culture in the entire number isolated 

 which closely approached Ashford's sprue organism, with the exception of 

 Culture 147.103 which gave the same reactions in sugar mediums but differed 

 in its morphologic characters and type of giant colony formed. In general, 

 however, the type of growth produced by the sprue organism resembles a 

 large number of the yeasts studied in that it forms a white, glistening, firm 

 surface which remains moist, heaped, and chalk-white. 



The pathogenic yeast of Simon also has many characters in common with the 

 sprue and thrush organisms. It forms the same type of surface growth and 

 produces similar reactions in sugar mediums, as well as the peculiar villous 

 growth in gelatin-stab culture. It was received too late in this investigation 

 to make a complete study of all its biochemical characters. 



Blastomyces dermatitidis is decidedly different in most of its characters 

 from any of the yeasts isolated, as well as from the other pathogenic yeasts. 

 The production of a dry, fluffy, aerial mycelium, commonly formed in old cul- 

 tures of this organism, is a character not possessed by any of the yeast-like 

 organisms under consideration. There is also a marked tendency of this fungus 

 to grow beneath the surface of the agar slant forming a tough, leathery, mycelial 

 layer from which arise tufts of hyphae, strongly resembling Indian wigwams. 

 The budding condition is not predominant in this fungus and, as stated later, 

 it is not to be considered as a yeast. 



The remaining pathogenic yeasts mentioned above differ from those isolated 

 from the intestinal tract in their cultural characters especially. While the 

 majority of the intestinal species form a distinctly chalk-white growth on 

 agar slants which becomes only slightly darker -with age, Saccharomyces hominis, 

 Torula humicola, and the pathogenic yeasts of Curtis, Foulerton, and Binot 

 develop more or less slimy growths which become brown, yellowish-brown, or 

 ash-gray in color. There are also marked morphologic distinctions between 

 these species and those of the intestinal tract. 



A comparison of the nonpathogenic yeasts listed in Table 2 with those from 

 the intestinal tract demonstrates that these 2 groups have many characters in 

 common. The chalk-white streak on agar slants is commonly developed by a 

 number of species in both groups, while the spreading Mycoderma type of 

 growth occurs in a number of the intestinal species, as well as in 'the true 



* The specimen of Oidium albicans used in this study was obtained from the St. Thomas 

 Hospital in London and was stated to be a typical culture from the tongue of a child 

 suffering from an undoubted case of thrush. (Letter from Dr. Frank Babtree, dated March 

 3, 1917.) This form does not liquefy gelatin readily, nor does it clot milk. Castellani ('16) 

 describes 7 'forms' of this species none of which liquefy gelatin, while 6 of them clot milk, 

 He states that the name 'Monilia albicans' should be reserved for the form which clots milk 

 and liquefies gelatin. He regards these forms as being different species, although he does 

 not name them, and is of the opinion that there is a plurality of species causing thrush. 



