The Senses of Animals. 



25 1 



molecules in a similar vibrating condition, giving rise to 

 similar colours and similar tastes." " Thus the chlorides 

 and sulphates of a series of similar elements — called a 

 group of elements by Mendeljeff — have similar tastes." 



The delicacy of the sense of taste in man has been the 

 subject of investigation by Messrs. E. H. S. Bailey and 

 E. L. Nichols.* They give the following table : — 



I. 



Quinine — 











Male observers 



detected 1 



part in 390,000 parts of water 





Female „ 



» 1 



„ 456,000 



„ „ 



II. 



Cane-sugar — 

 Male observers 





199 







Female „ 



»5 *• 



204 



9> SJ 



III. 



Sulphuric acid — 











Male observers 



„ 1 



2,080 



» )' 





Female „ 



>5 *■ 



3,280 



„ ,, 



IV. 



Bicarbonate of sodium — 









Male observers 



;? A 



98 



„ „ 





Female „ 



5J ■*■ 



126 



,, „ 



V. 



Common salt — ■ 











Male observers 



1 



2,240 



„ ,, 





Female „ 



1 



„ 1,980 



» » 



The above figures represent means or averages of a 

 great number of individuals. There was very considerable 

 variation for some tastes. In the case of the bitter of 

 quinine, the maximum delicacy was the detection of 1 part 

 in 5,120,000 parts of water; the minimum 1 part in 

 456,000 parts of water. Except in the case of salt, the 

 sense was more delicate in women than in men. It is not 

 stated whether the men tested were smokers. 



It does not seem necessary to say anything concerning 

 the sense of taste in the lower mammalia. 



In birds and reptiles the sense of taste does not appear 

 to be highly developed. Parrots are, perhaps, better off 

 in this respect than the majority of their class ; and the 

 ducks have special organs on the edges of the beak, which 

 seem to minister to this sense. A python at the Zoological 

 Gardens, partially blind owing to a change of skin, is said 

 to have struck at an animal, but to have only succeeded 



* See Nature, vol. xsxvii. p. 557. 



