INFLUENCE OF THE MEDIUM 143 



It is generally known that lowering of the temperature 

 of an animal heart causes the beating to become less rapid. 

 This is perfectly parallel to the falling off in heart activity 

 in strong solutions, as observed by Miss Shively and recorded 

 by Loeb (page 129). 



In my own experiments on Stigeoclonium, 1 it was found 

 that the organism responds to drying on a porous plate in 

 exactly the same way as it does to change from a weak to a 

 strong solution. 



Recently, Greeley 2 has shown that by cooling Stentor 

 coerulcus the same cessation of activity and rounding up 

 was brought about as when the animals were subjected 

 to the action of concentrated solutions. However, the 

 effect of the solution was not reversible, for the animals 

 could not be revived. The same author has shown that 

 cold plasmolysis in Spirogyra is reversible, that a rise in 

 temperature brings the plasmolyzed alga back to its normal 

 condition. 



During the summer of 1901 Greeley 3 was able to pro- 

 duce artificial parthenogenesis of Echinoderm eggs by 

 merely keeping them for a time at a low temperature. In 

 these cold-fertilized eggs, development went as far as in 

 normally fertilized ones under artificial conditions. 



In general, then, it may be concluded that there is a 

 striking analogy between the responses obtained in these 

 various organisms by treating them with strong solutions 

 and by extracting water from them in any other way. How 

 much further we may go in this, remains for future experi- 

 ment to show. 



1 B. E. LIVINGSTON, " Further Notes on the Physiology of Polymorphism in Green 

 Algse," Bot. Gaz., Vol. XXXII (1901), pp. 292-302. 



2 A. W. GKEELEY, " On the Analogy between the Effects of Loss of Water and 

 Lowering of Temperature," Am. Jour. PhysioL, Vol. VI (1901), pp. 122-8. 



3 A. W. GREELEY, "Artificial Parthenogenesis Produced by a Lowering of the 

 Temperature," Am. Jour. PhysioL, Vol. VI (1902), pp. 296-304. 



