The Senses of Animals. 251 



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 : 



1. Quinine 



Male observers detected 1 part in 390,000 parts of water. 

 Female 1 456,000 



II. Cane-sugar 



Male observers 1 199 



Female 1 204 



III. Sulphuric acid 



Male observers 1 2,080 



Female 1 3,280 



IV. Bicarbonate of sodium 



Male observers 1 98 



Female 1 126 

 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 

 160,000 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. xxxvii. p. 557. 



