iv AUTHOR'S EXPERIMENTS 189 



nessed facts which are exactly parallel l while compar- 

 ing the influence of increased temperature on Crustace- 

 ans of different species, some dwellers on the shore, 

 and others at some distance ; the former withstand tem- 

 peratures which the latter are unable to resist, and 

 the reason may be found in the fact that the shore- 

 inhabiting animals are liable (my experiments were 

 made in Banyuls on the Mediterranean coast) to be 

 much warmed in the pools or even in the surface water, 

 by the heat of the sun. 



In the case of heat, as well as that of salt, there seems 

 to exist a marked adaptation of the organisms, and 

 this adaptation I have also investigated in regard 

 quite different animals and conditions. 2 For instance 

 while tadpoles soon die when introduced into water 

 containing some amount of common salt, it is easy to 

 enable them to survive by using at first very dilute 

 solutions to which a small quantity of salt is added 

 every day or every second day. But even when the pro- 



1 Henry de Varigny, Ueber die Wirkung der Temperaturerhohungen 

 auf einige Crustaceen. Centralblatt f. Physiologic, 1887. 



2 Cf. Henry de Varigny : Influence exercee par les Principes contenus 

 dans FEau de Mer sur le Developpement d? Animaux d'Eau douce. 

 Comptes Rendus, 1883, vol. xcvii. p. 94.. But many of the results here 

 recorded have been obtained at a later date, and the paper in which they 

 have been embodied, read before the meeting of the French Association 

 for the Advancement of Science, at the meeting held in Rouen, 1883, 

 under the title : Sur V Action des Variations de Milieu sur les Animaux 

 d'Eau douce, has remained unpublished. 



UNIVERSITY 



