SMELL — FIELDWORK AND EXPERIMENTS IO3 



that of burnt rubber, and I think this is as good a simile as 

 any. 



Our common toad is reluctant to eat the yellow- and red- 

 banded worms known commonly as "brandhngs". These 

 live chiefly in manure heaps and have a smell which is easily 

 detected by our own noses. Curiously enough, fish of several 

 species do not hesitate to take these worms, and this is a 

 good example of how a smell may be offensive to one kind 

 of animal and attractive to another. 



Newts can smell well, and if a tank containing them is 

 placed in darkness, they will find and eat worms without 

 difficulty. This is an easy experiment to carry out, and it 

 may be done with newts in water or when they are in their 

 terrestrial state. 



Birds 



Most books on the habits of birds are lacking in references 

 to their degrees or variations in smelling ability ; and this is 

 probably because they are generally considered to be defi- 

 cient in this sense except for the species already referred to. 

 I know that my co-author considers that some birds — notably 

 petrels and albatrosses — can smell as well as we can ; but 

 that is not necessarily a great achievement when we realize 

 how feeble are our own noses, both in delicacy and dis- 

 crimination. 



I am sure that a series of experiments designed to test 

 various birds in respect of their powers of scenting would be 

 well worth while. 



Mammals 



It is when we come to the subject of testing and observing 

 the uses of scent in mammals that we are up against a very 

 complex aspect of the study of senses. As mammals all have 

 their own natural scent specific to their particular kind, and 

 as in addition some have scent glands which are used for 

 marking out territory and to aid in mating, we have to be 

 careful, when discussing mammalian scent, that we are 

 certain what kind of scent we are referring to. 



Probably the best way to observe mammals following 



