YEAST-LIKE FUNGI OF HUMAN INTESTINAL TRACT 31 



pathogenic only when recently isolated or after it has passed through 

 some susceptible animal. This may explain the negative results of 

 others in their injection experiments. 



In order to test and extend the results obtained by Neumayer and 

 Ashford, and especially to gain more insight into the fate of the 

 ingested yeasts, a number of experiments were undertaken with the 

 yeasts previously isolated or with certain commercial yeasts having 

 well defined characters. 



The yeasts selected were those having some distinctive character so 

 that they could be quickly recognized when reisolated from the feces. 

 The following species were used: 



1. S. glutinis (red) 



2. 51 (red and forming a peculiar wrinkled colony) 



3. S. anomalus (distinctive ascospores) 



4. 11.5 (produces ascospores of a peculiar type and has a dis- 



tinctive growth) 



5. D (a culture of Dr. Ashford's sprue organism) 



A number of other species were used but since the results do not differ 

 in any way from those here obtained they are not included. The methods used 

 and the results obtained for the first 4 organisms given were identical and will 

 be discussed together. The yeasts were grown on an agar slant for several 

 days and then a mass about the size of a grain of corn was swallowed. Cul- 

 tures were always ingested within a few hours after the passage of stools and 

 in most cases the first sample of feces was obtained within 30 hours. Samples 

 also were taken from stools just previous to feeding and plates were made 

 from these in order to exclude the possibility of any species being present in 

 sufficient quantity to interfere with the experiment. Since the person used 

 had been previously tested a number of times for other isolations, it was 

 known that few yeasts were normally present in the feces. 



Ten plates were made from 10 different portions of the stools in the case 

 of each sample. Subsequent stools during the course of a week or 10 days were 

 tested in the same manner. After feeding 1 species, a period of several days 

 was always allowed before the next feeding, in this way eliminating the possi- 

 bility of confusing the 2 species fed. The tests were made on a person in 

 good health and showing a history free from gastro-intestinal troubles in 

 recent years. No effort was made to control the diet which consisted of the 

 normal mixed food of a healthy person with a large amount of carbohydrates. 



The first stools following the feeding always contained large numbers of 

 the particular yeast ingested. All the plates gave numerous colonies and most 

 of them usually showed over 50% positive results, while many developed colonies 

 of the yeast ingested at 100% of the points of contact. The yeasts seemed to 

 be fairly evenly distributed throughout the stools, although microscopic exam- 

 ination showed them more abundant in some mounts than others. Under the 

 microscope the majority of the cells were seen to be of a faint yellow color 

 and few of them were budding. They did not appear to be in an active grow- 

 ing condition, but most of them seemed to be living. A careful examination 

 of the plates was always made to discover, if possible, foreign types of yeasts. 

 In several cases when pink yeasts were fed, 3 or 4 white colonies in the entire 

 10 plates appeared, and the reverse was true when white yeasts were ingested. 



