STUDIES IN ARTIFICIAL PARTHENOGENESIS. 1 95 



movements of granules through the cytoplasm. The only 

 explanation of such a marked increase in viscosity is that gela- 

 tinization or coagulation has taken place within the egg. Un- 

 doubtedly exosmosis causes some constituent of the cytoplasm 

 to change from sol to gel. 



Endosmosis was also found to cause coagulation, either when 

 it resulted from a dilution of the outer medium, or when it was 

 the result of a lowered surface tension of the vitelline or plasma 

 membrane. This could be demonstrated either by observing 

 the cytoplasmic flow from compressed eggs, or by noting the 

 granular movements in centrifuged eggs. Numerous experi- 

 ments were made with distilled water. In an experiment of 

 June 30, 1914, a square piece of glass which had been broken 

 from a slide was used to compress the eggs. It weighed 1.31 

 grams. The piece of glass was held between the thumb and 

 forefinger, so that its one edge rested on the slide just to one 

 side of the coverslip which covered the eggs under observation. 

 At the desired time, the glass piece was dropped and the com- 

 pressed eggs could then be immediately observed. Normal 

 eggs were deprived of their jelly by shaking them 6 or 8 times in 

 a test-tube, and were then subjected to the pressure of the piece 

 of glass as just described. The eggs all ruptured, the contents 

 flowing out for a distance of about 60/1. Eggs (from the same 

 female) were then dropped into distilled water at 10:28 A.M. 

 At io:28f any jelly which may have remained around them 

 was removed by shaking the eggs. At 10:29^ the eggs were 

 subjected to the pressure of the same piece of glass which had been 

 used in the case of the normal eggs. They resisted the pressure 

 and remained circular or nearly circular in outline. In the eggs 

 observed, membrane elevation had not taken place. The 

 greater resistance to pressure of the eggs treated w r ith distilled 

 water is an indication of their increased viscosity. The eggs 

 tended to remain spherical, they showed a definite elasticity. 

 Similar observations showing increased viscosity after treatment 

 with distilled water, were made a number of times both in 1913 

 and 1914. 



On July 25, 1914, at 3:59 P.M., 7 drops of an egg suspension 

 were dropped into 15 c.c. of distilled water. The eggs in the 



