196 L. V. HEILBRUNX. 



distilled water were then hastily pipetted into one tube of the 

 centrifuge, the other tube contained untreated eggs. The 

 centrifuge was started at 4:00^ P.M., and for 25 seconds the 

 tubes were revolved at a rate of 156 revolutions per second. 

 The eggs in distilled water were examined as soon as possible 

 (about half a minute later). They showed not a sign of strati- 

 fication. Most of the pigment had been lost as a result of the 

 action of the distilled water, but high power examination showed 

 that the pigment-bearing granules still retained some pigment. 

 These granules were scattered all through the cell. On the 

 other hand the normal eggs showed the typical stratification. 

 The viscosity of the cytoplasm had therefore increased enor- 

 mously in the eggs treated with distilled w r ater, so that the 

 granules were prevented from wandering through it. In another 

 experiment (July 22, 1914) the eggs w r ere transferred back to 

 sea-water before being centrifuged. At 3:51 P.M., 5 drops of 

 egg suspension were added to 15 c.c. of distilled water. At 

 3:55 P.M., some of these eggs were removed from the distilled 

 water and placed into sea-water again. The eggs thus trans- 

 ferred were the ones studied; they were placed into one tube of 

 the centrifuge, normal eggs occupying the other. Beginning at 

 3:59^ P.M., the tubes were revolved 165 times per second for 

 30 seconds. Upon examination it was found that whereas the 

 normal eggs were completely stratified, not a sign of stratification 

 could be observed in the eggs which had been exposed to distilled 

 water. Evidently endosmosis, following immersion in distilled 

 water, leads to a gelatinization or coagulation in the cytoplasm. 

 This effect is also produced when endosmosis follows a lowered 

 surface tension of the plasma membrane. A drop of egg sus- 

 pension was stirred up with a drop of chloroform, and the eggs 

 rapidly increased in diameter. When subjected to the pressure 

 of a piece of glass broken from a slide, the eggs flattened out but 

 remained perfectly circular in outline. The same result was 

 obtained if toluol was used instead of chloroform. The eggs 

 under pressure behave like eggs which have been coagulated by 

 some typical coagulant, e. g., HgCl 2 . On the other hand, when 

 the normal eggs were subjected to the pressure of the same piece 

 of glass, the cytoplasm flowed out a considerable distance. The 



