Il8 THE MEANING OF EVOLUTION 



the attempt to capture anything which must be so 

 ignominiously allowed to escape. If one's clothing is 

 well saturated with it, it is nearly useless to hope to 

 remove the odor. A dog will carry the smell for sev- 

 eral weeks. For a long time it will be so strong as 

 to make him an unfit denizen of the house. Even 

 swimming in deep water does not remove it. After 

 two weeks, although he may seem to be practically 

 free from the odor, a light rain will bring it all out 

 again and make him nearly as offensive as before. 



Not as prompt in its action, but in the end nearly 

 as effective, is the protective device which the toad 

 sometimes uses to his distinct advantage. May I 

 be pardoned a personal account of this particular 

 feature. It was my good fortune to be for a short 

 time a student in a class taught by Edward Drinker 

 Cope, one of the most brilliant of our American bi- 

 ologists. Prof. Cope mentioned in class the fact that 

 the Batrachians (the group to which the toad be- 

 longs) have in many cases the power to emit from 

 their skin a fluid which is sufficiently nauseous to de- 

 ter an animal from eating the creature that secretes 

 it. Upon such authority as this, I had no hesitancy 

 whatever in repeating Cope's statement. One morn- 

 ing I had a class in the field studying the ground ivy, 

 whose dainty blue flowers were lifting themselves out 

 of the dewy grass. While we were thus engaged, a 



