Artificial Parthenogenesis in Starfish Eggs 413 



maturation eggs may be found to respond to some such form of 

 treatment. As yet I have made no investigation of these relations. 

 Probably the most appropriate form of treatment will be found 

 to vary at different stages, according to the physiological condi- 

 tion of the egg. The experiments about to be described indicate 

 that the state of oxidation of the egg-protoplasm is a most impor- 

 tant factor; and it seems not unlikely that the above differences in 

 response at different periods may be found to depend largely on 

 varying conditions of oxidation at different stages. 



Effects of Combining Momentary Elevation of Temperature with 

 the Action of Cyanide Solutions 



The supposition that momentary elevation of temperature pro- 

 duces its effects on the eggs through an acceleration of oxidation 

 processes suggested itself early in the investigation. The beauti- 

 ful experiments of Loeb^- had shown the importance of the presence 

 of oxygen in the action of hypertonic solutions on the Strongylo- 

 centrotus egg. I therefore tested the effects of warming starfish 

 eggs under conditions that exclude the influence of accelerated 

 oxidations. For this purpose sea-water containing potassium cya- 

 nide to 2W0I) concentration was employed. In this medium intra- 

 cellular oxidations are greatly retarded if not almost altogether 

 suppressed, as shown by the fact that mature eggs remain for 

 days without undergoing the typical coagulative disintegration, 

 which, as Loeb has shown, is dependent on oxidations. In the 

 following experiments the eggs were warmed to 35° for 70 seconds 

 while in KCN sea-water, to which they were transferred in some 

 cases directly from normal sea-water, in others from 2i\jjj KCN in 

 which they had been allowed to lie for varying periods of time. 

 After warming, the eggs were transferred in some experiments 

 directly to normal sea-water, in others to 0/00 KCN at normal tem- 

 peratures, whence, after varying intervals, they were transferred 

 to sea-water. 



The influence of previous treatment with cyanide solutions on 

 the development of eggs warmed momentarily in normal sea-water 



^Loeb: Biochemische Zeitschrift, vol. i, pp. 189, 1906, et seq., and preceding papers in University 

 of California Publications. 



