HEREDITY 91 



birds, when such cries are uttered, in conjunction 

 with a careful suggestion of the tones employed, the 

 reader will be enabled to understand my meaning, 

 even if he have not previously been familiar with the 

 actual cries indicated. I feel sure that if any one, 

 able to distinguish the commoner British birds, will 

 take a stroll in the country, provided with a small 

 telescope, or a powerful pair of field-glasses, and will 

 notice all the cries of birds heard during that single 

 excursion, especially if he be accompanied by a dog, 

 he will hear much illustrative of my remarks. It is 

 advisable that a dog should be his only companion ; 

 for if a friend be near, conversation will arise, with 

 the result that the notes of birds will not be heard, 

 and in any case the birds will be scared away sooner 

 than if disturbed by only one person. The dog, 

 running among wayside bushes, will occasion the 

 utterance of many interesting cries of alarm. 



The study of this subject enables us to perceive 

 with increasing clearness distinctions which are cor- 

 respondingly subtle : this is a truism which needs 

 no demonstration ; and it applies with equal force to 

 the observation of bird-song, or to that of any other 

 matter. An observer can educate his memory to the 

 recognition of a multitude of cries, and even of vocal 

 inflections, which are common to different species. 



