YEAST-LIKE FUNGI OF HUMAN INTESTINAL TRACT 41 



DESCRIPTIONS OF NEW SPECIES OF YEASTS 



Over 100 cultures of unknown yeast-like fungi were studied during the 

 present investigation. The cultural and morphologic characters of all these 

 were studied sufficiently to demonstrate that there were few absolute duplica- 

 tions in the entire number of cultures. A detailed investigation of a group of 

 these cultures has been presented in a previous section. Specific descriptions 

 of some of these, together with a few other interesting forms, will be given. 

 Cultures of the described species have been sent to the American Museum of 

 Natural history, New York, the Centralstelle fur Pilzenkulturen, Amsterdam, 

 Holland, and the United States Department of Agriculture, Bureau of Plant 

 Industry. An additional set together with dried type material has been deposited 

 in the herbarium of the Department of Botany, University of Illinois. 



PSEUDOSACCHAROMYCES STEVEN SI SP. NOV. 



Morphology. In both young and old cultures the cells are narrowly ellip- 

 tical, oblong, or apiculate; cytoplasm, very granular; vacuoles, not distinct 

 except in old, swollen cells; no elongated cells or false mycelium are formed 

 under any condition of culture. Budding occurs only at ends, by elongation 

 and swelling of the apiculate portion. The size is 2 X 5 microns.* No endo- 

 spores are formed. (Plate 3, Figs. 10, 11.) 



Cultural Characters. On glucose agar the streak is filiform, glistening, white, 

 flat, and smooth. The growth is slow, and the colony becomes dirty-gray with 

 age. In gelatin no liquefication occurs; the growth is filiform. In beerwort 

 and sugar mediums there is slow development, with no evidence of growth 

 except a slight sediment. The giant colonies are very small. (Plate 6, Fig. 9; 

 Plate 8, Fig. 18.) 



Physiologic Properties. There is no fermentation of glucose, levulose, 

 sucrose, lactose, raffinose, galactose, or maltose. Mo decided change in acidity 

 occurs in these sugars, dextrin, or yeast water. There is no change in litmus 

 milk. 



The culture was isolated from human feces. (Culture 9.101; Type Specimen 

 1; Type Slide 9.) 



ZYGOSACCHAROMYCES BISPORUS SP. NOV. 



Morphology. In young liquid cultures the cells are oval or ovate ; in old 

 cultures they assume various forms with numerous conjugating, but usually 

 no sporulating cells. Elongated cells are common, but there is no mycelial 

 formation. Budding occurs from end or side. The size is 4 X 6.5 microns. 

 Spore formation occurs on carrot slants at room temperature. Conjugation is 

 most common previous to spore formation, but parthenogenesis is not rare. 

 There are 2-4 ascospores, most commonly 2. (Plate 4, Fig. 8.) 



Cultural Characters. On glucose agar the growth is spreading, dull, flat, 

 and white; later it becomes brownish with small, scattered, wart-like promi- 

 nences and more glistening surface. There is a filiform growth in gelatin stab 

 and liquefication in beerwort gelatin in 3 weeks. Pellicle is present on beerwort 

 and some sugar mediums. Giant colonies may be seen in Plate 6, Figure 6. 



* The size given is not the average of a large number of measurements, but is the 

 result of an attempt to select a single cell which will represent the size and proportions of 

 the most numerous cells of a fairly uniform character. This plan is believed to give more 

 definite results than could be obtained by measuring numerous cells and averaging these. 

 This conclusion is based on a study of both methods. 



