iQisl C. H. Crabill and H. S. Recd 33 



starch-agar. Inulin is soluble in hot water and consequently dis- 

 solves during sterilization. Evidence of the ability of the organ- 

 isms to dissolve inulin in this medium is afforded only by the amount 

 of growth and spore production. 



Only a few fungi have been tested, but some of them grew well 

 upon this medium. See Table 2. 



Emulsins : glucoside-splitting enzymes. The glucosides are 

 complex organic Compounds capable of hydrolysis. Various end 

 products, one of which is always a sugar, are the result. Since the 

 glucosides are readily soluble, the agar containing them is trans- 

 parent and the action of enzymes can be determined only indirectly. 

 If the organisms can use the glucosides as sources of carbon, it is 

 assumed that cleavage of the glucosides occurs in such consumption. 

 The glucosides in a pure State are added to the stock agar to the 

 amount of i percent, and plates poured and inoculated. 



Esciilin-agar. A bluish color pervades the agar made with 

 esculin. In the event of the successful growth of the organism this 

 blue color is reduced, sometimes throughout the plate. The suc- 

 cessful growth of the organism is, however, a better indication of 

 its ability to produce emulsin than is the color reduction. 



Arbutin-agar. Arbutin, by hydrolytic cleavage, yields sugar 

 and hydroquinone, which gives a brown color. The successful 

 growth of the organism, and production of a brown stain on agar 

 containing this chemical as the only source of carbon, are regarded 

 as evidences of its ability to produce emulsin. 



Amygdalin-agar. Success or f ailure to grow on this medium is 

 our only indication of the ability or inability of an organism to pro- 

 duce emulsin. Typical data are given in Table 3. 



LiPASE. Demonstration of the presence of lipase depends upon 

 its power to split fats into glycerol and free fatty acids. The pres- 

 ence of the acids may then be shown by a convenient indicator. 



Litmus-cream-agar. Fifty c.c. of 48 percent Separator cream 

 are diluted to 600 c.c. with distilled water and fractionally sterilized 

 in an Arnold sterilizer. Twenty gm. of agar-agar are melted in 400 

 c.c. of water; the liquid is filtered, sterilized and added to the di- 

 luted Cream while hot ; and enough sterile litmus Solution is poured 

 into the fluid to impart a deep blue color. Plates are poured, and 



