219 



this emulsion was placed on a tliin support, each organism 

 could be seen to be enclosed in a cell consisting of a droplet 

 of nutritive medium surrounded by oil. The objection 

 mentioned for the previous method applies to this one also. 



Perhaps one might have success by spraying the cultures 

 in thin sheets into liquid air by means of a syringe with a 

 flattened and adjustable jet. 



As for the methods of drying, we used, besides that which 

 consists in allowing the preparation to evaporate in the 

 air or in desiccators containing various concentrations of 

 sulfuric acid, also the plasmolytic method of immersing 

 the preparation into a solution of salt or of sugar. 



3. Experiments and Results. We undertook a first series 

 of experiments with euglenae. The organisms were first 

 concentrated by centrifugation. A small drop of the con- 

 centrated culture was thereupon placed on a glass slide 

 and left to evaporate in the air till only a swarming mass 

 of animals remained. The preparation was then dipped 

 into liquid air and after this into water at 20° or at 40°. 

 No euglena ever came back alive from the ordeal. Think- 

 ing that the organisms contained too much water, we tried 

 to carry the evaporation still farther or to reduce the water 

 content by adding to the droplet concentrated solutions of 

 sugar. But concentrations which killed the euglenae 

 within one minute, did not suffice to produce the desired 

 result. The use of strips of mica instead of glass supports, 

 to lessen the heat capacity, was likewise ineffectual. On 

 the whole, all our attempts to revive euglenae in the vege- 

 tative state were unsuccessful. The organisms were ordi- 

 narily not deformed, but they showed no sign of life. 

 Whether they had actually been vitrified or frozen is 

 uncertain. 



We next repeated with paramecia all the experiments 

 made with euglenae. The results were completely nega- 

 tive. But, while the euglenae did not suffer any deforma- 

 tion by the treatment, the paramecia always did, and often 

 they were found completely broken in pieces when taken 

 out of the liquid air. 



