I3O ARTHUR W. GREELEY. 



ing the effect of the solution upon the egg at different tempera 

 tures. 



All the salt solutions used in the experiments on artificial par- 

 thenogenesis may be divided into two classes according to their sup- 

 posed action upon the protoplasm : first, those solutions used at 

 a higher concentration than that of sea-water which produce par- 

 thenogenesis through the extraction of water from the protoplasm ; 

 and, second, those solutions used at the same or at a less con- 

 centration than that of the sea-water which affect the egg through 

 the specific action of ions. In the light of the observations already 

 made on the effect of changes in temperature upon protoplasm, 

 it was a point of considerable interest to determine whether varia- 

 tions in the temperature would affect the action of each of these 

 classes of solutions upon the egg in the same way. Since the 

 speed of a chemical combination varies directly with the temper- 

 ature, it might be supposed that the specific action of an ion 

 upon the egg would be inhibited or slowed by lowering the 

 temperature, and accelerated by raising the temperature, up to 

 the point where the protoplasm begins to go into heat-rigor. 

 And similarly, since a reduction of the temperature extracts 

 water from the protoplasm, the action of concentrated solutions 

 upon the egg ought to be increased by a lowering of the tem- 

 perature. Such a disparity between the effect of variations in 

 the temperature upon the chemical and osmotic methods of pro- 

 ducing artificial parthenogenesis was, however, not found to 

 hold. A lowering of the temperature, for example, inhibits or 

 slows the action of all solutions upon the egg, whether they are 

 isotonic or hypertonic to sea-water. 



The experiments were performed at Woods Hole, during the 

 summer of 1902, with such temperatures as could readily be ob- 

 tained in the laboratory with the aid of an ordinary hot-air oven 

 and a refrigerator. Four temperatures were used ; namely, 30 

 C., 23 C., 11 C. and 2 C. The solutions to be used in the 

 experiments were prepared and divided among four dishes. The 

 dishes were placed at these four temperatures, and allowed to 

 stand forty-five minutes before the addition of the eggs. The 

 eggs were then distributed among the various dishes at the dif- 

 ferent temperatures, and after certain intervals of time, were re- 



