22 HARRY WARREN ANDERSON 



the giant colonies is simple. A 200 c.c. Erlenmeyer flask is filled to a depth 

 of 1.5 cm. with a 12% beerwort gelatin. A drop from a fresh beerwort culture 

 of the organism is placed in the center of the gelatin. The colony is allowed 

 to develop for 3 weeks or longer and is then photographed. Geiger ('10) 

 recommends the employment of potato and sauerkraut gelatin in addition to 

 the beerwort gelatin. The types of giant colonies produced are fairly constant 

 according to the authors mentioned. In the present investigation a slightly 

 different method was employed. In addition to beerwort gelatin, glucose agar 

 (2% agar with 2% glucose, and an acidity of + 1) was used and Petri dishes 

 of a uniform depth and diameter were substituted for the flasks. Exactly the 

 same amount of medium was placed in each dish, and cultural conditions were 

 kept uniform. 



SPECIAL STUDY OF 20 REPRESENTATIVE YEASTS 



The large number of cultures obtained rendered an intensive study of the 

 entire number impracticable. Moreover, the primary object of the investigation 

 was to work out a scheme by which these yeast-like organisms could be 

 classified in future investigations rather than to make a detailed study of all 

 organisms isolated from the intestinal tract. In order to test the usefulness 

 of the plan proposed, a more intensive study of 20 cultures was made. These 

 were all of the 'white' type except Saccharomyces hominis which gives a slimy 

 yellowish growth on agar slants. Most of these were also of the white glisten- 

 ing type since it was desired to undertake the separation of species which 

 resembled each other closely in gross characters. Several named species were 

 also included in this study to serve as 'controls'. An outline of the procedure 

 used is given. Tables 3, 4, 5, and 6 are not arranged in the order of this out- 

 line, but are given in the form which was found most convenient in sum- 

 marizing the results of all the experiments. 



OUTLINE OF PROCEDURE 



1. Morphology 



1. In young cultures of solid and liquid mediums 



2. In old cultures of solid and liquid mediums 



3. In hanging drop cultures 



4. Ascospore formation 



2. Cultural Characters 



1. Gelatin-stab cultures 



2. On agar and carrot slants 



3. In liquid mediums aside from milk 



(a) pellicle, ring, and grease-film formation 



4. Giant colonies on beerwort . gelatin and glucose agar 



3. Physiology (biochemical properties) 



1. Carbohydrate reactions, fermentation and acid reactions 



2. Litmus milk reactions 



3. Gelatin (included in cultural studies) 



In Table 3 there is given a summary of the chief cultural and physiologic 

 characters of the organisms together with the sources of the cultures. The num- 

 bers and letters to the left are used in subsequent tables and need some 

 explanation. Culture 2.5 was isolated from a patient diagnosed as sprue and 

 has been treated in some detail earlier in this article. The culture was sent 

 to Dr. Ashford* who stated that it was the same as his sprue organism. Cul- 

 ture D is a typical sprue organism received from Dr. Ashford, and is included 

 for comparison. The next 14 cultures were isolated from normal persons 

 with the exception of 158, which was from the case discussed previously in 

 which repeated isolations were made from a woman of advanced age who 



Letter dated Oct. 18, 1916. 



