in GREEN AND BROWN FROG 135 



with gastric glands which are exactly similar, the 

 brown certainly produces a much larger amount of 

 pepsin. These are differences which may be of great 

 importance in the life of the animals or may go 

 with others yet unknown to make considerable differ- 

 ences yet nothing in the external character of the 

 animals would lead us to suppose that they were 

 present. 



Among the facts which illustrate this physiological 

 variability I shall quote a few more. We all are 

 acquainted with the fact that while many varieties of 

 grape-vine are killed by some fungus or insect Phyl- 

 loxera, for instance others do not suffer at all, or 

 at least, as a rule, withstand the unfavourable effects. 

 We know also that while the venom of a snake is 

 deadly for most other snakes, it is not so for the same 

 species, as Surgeon Waddell x has recently shown with 

 great care ; we have all heard of cases when the same 

 plant is toxic for some animals and is not so for 

 others. Willoughby in his Ornithologia 2 says that the 

 common quail eats hellebore and water-dropwort 

 (Cicuta] without danger ; Daniel Duncan 3 says the 

 same of the same animal ; water-dropwort is not 

 dangerous for goats, nor tobacco-leaves for oxen, 



1 Are Venomous Snakes Autotoxic ? Calcutta, I 



2 Francisci Willughbeii Ornithologia, Libri Hi. 1676. 



3 La Chymie Naturelle^ on I Explication Chymique et Mechaniqtu de 



la Nonrritnre de I Animal, 



UNIVEBSITI 



