1914] Sharp: Diplodinium ecaudatum 53 



without causing death, but, although this may be true for some of the 

 species, it certainly does not hold for the species of Diplodinium,. 

 Fiorentini (1889) says nothing of the manner in which he conveys 

 the stomach fluid to the laboratory except that it is in test-tubes, but 

 he does explain how he keeps the liquid warm in the laboratory. He 

 says : ' ' For keeping the test-tubes at the temperature indicated above 

 (30 to 35° C) we have recourse to a system of immersion in a vase 

 of hot water, which is renewed from time to time, or still better, we 

 keep it in an oven at a constant temperature regulated at 35° C." 



Schuberg (1888) gives no detailed description of his method of 

 keeping the animals alive while under observation. He speaks of a 

 heated microscope stage ("geheizten Objecttisch"), but does not tell 

 how he keeps this stage hot nor does he tell how long he is able to 

 keep alive the animals under observation. Fiorentini says that he had 

 recourse to the Schultze warm stage, and notes that he was by this 

 method enabled to keep the animals under observation alive for a 

 long time, "even for a whole hour at a time." Fiorentini also used 

 another method which he explains as follows : ' ' First I heat the glass 

 slide at a small lamp until it is lukewarm; then I put a drop of the 

 material to be observed upon it and cover it with a cover glass. Then 

 with a pipette I take boiling water from a capsule which I keep near 

 me and drop this hot water on the glass slide in such a manner that 

 it will not mix with the fluid underneath the covergiass. The hot 

 water thus placed upon the slide allows me to maintain for a long 

 time the glass and the material being observed at a sufficiently high 

 temperature so that I am permitted to make my observations on the 

 living protozoans" (translated from the Italian original). And 

 further he says : ' ' Once the slide becomes cold one begins again with 

 a new preparation." And again: "This method is indispensable dur- 

 ing winter. In summer, however, it is sufficient to heat up the slide 

 to get a preparation which keeps long enough to permit one to make a 

 long observation." This method, Eberlein states, he was unable to 

 use; instead he employed a glass plate which he laid on top of the 

 stage and on top of this he placed his slides. The glass plate he heated 

 by placing two small lamps under the projecting corners. Eberlein 

 says that he soon became expert enough to tell the proper temperature 

 of the glass plate through the sense of touch. 



Bundle (1895) in his report on the ciliates from the caecum of 

 the horse says very little about the methods which he employed to 

 keep the animals alive under observation except that he sometimes 



