RECENT SCIENCE. 629 



with a decrease of vital energy, especially if we take into account 

 the permanent white colors of domesticated animals in arctic 

 regions (such as the Yakutsk horse), which can not be dependent 

 upon natural selection ? Some recent observations give a certain 

 support to this supposition. Thus we now learn that rabbits 

 which have been taken to the Pic du Midi Observatory (9,500 feet 

 above the sea level) have given in seven years a race somewhat 

 different from their congeners in the surrounding plains. They 

 are a little smaller, have less developed ears, and their fur coats 

 are of a lighter color and very thick. Moreover, the very consist- 

 ence of their blood has undergone a notable change. It contains 

 more iron, and possesses a greater power of absorption for oxygen.* 

 An anatomical change is thus produced by the environment ; and 

 no naturalist will doubt that, if the race continues to multiply for 

 a great number of years in the same conditions, it will maintain 

 its present characters or develop new ones on the same lines, the 

 more rapidly so if natural selection eliminates the less adapted 

 individuals. 



A few more additions in the same direction may be found in a 

 valuable work recently published by F. E. Beddard.f Thus, he 

 mentions the researches of Dr. Eisig, \ who has endeavored to 

 explain the ground colors of some animals as dependent upon 

 their food, and has shown, for instance, that the yellow color of 

 an annelid which is living on a yellow marine sponge (a color 

 which might be explained as protective for the parasite) depends 

 upon the yellow pigment of the sponge absorbed by the annelid. 

 The prevalence of crimson colors among some fishes in a certain 

 part of the New England coast, which is covered with scarlet and 

 crimson seaweeds, is explained by J. Browne Goode by the red 

 pigment derived by the crustaceans from the algae with which 

 their stomachs are full, the crustaceans being devoured by the 

 fishes. And the experiments of Mr. Guyson relative to the effects 

 of different food plants upon a number of species of moths, 

 as well as those of Mr. J. Tawell upon important modifications 

 produced by food in the larvae of the large tortoise-shell butterfly, 

 both mentioned in the same work, are attempts in a most im- 

 portant but very young branch of experimental morphology. 



Another series of researches is now being made with the view 

 of more deeply penetrating into the physiological causes of animal 

 coloration. Thus, it is a fact well known to fishermen, and now 



* Comptes Rendus, January 2, 1891, tome cxii. 



■{■ F. E. Beddard, Animal Coloration ; an Account of the Principal Facts and Theories 

 relating to the Colors and Markings of Animals, London, 1892. 



% Fauna und Flora des Golfes von Neapel : die Capitelliden, quoted by Mr. Beddard, 

 he. cit., p. 101. 



