No. 634] ORAL MEMBRANES OF GLAUCOMA 429 



microns. 1 These, however, were very rare, and did not 

 number more than perhaps a dozen individuals among 

 several hundred. 



Glaucoma is a fairly common protozoan. Its usual 

 habitat is in stagnant water, particularly pond water in 

 which there is considerable decaying aquatic vegetation. 

 The writer has found it abundant in the brackish water 

 of a peat swamp. It commonly occurs wherever there 

 are also numbers of small flagellates. Samuelson ('57) 2 

 says that he has reared large numbers of them in an in- 

 fusion made from cabbage leaves and distilled water. 

 Cultures of Glaucoma were prepared in the laboratory 

 by the writer by allowing water, containing cattails, ponds 

 lily leaves, and Elodea to become putrid. Numerous 

 GlaucomcB were found congregated in the grayish scum 

 that overspread the surface of the infusions, where they 

 were engaged in feeding upon the bacteria, which seems 

 to form the bulk of their food. 



It was necessary to keep individual Glaucomce under 

 observation over extended periods of time, and this was 

 accomplished by means of a device whose utility was such 



