jfenner both right and wroHg. 115 



But the second is what in many cases will come just 

 to suit it about the beginning of May. Jenner would 

 give the cuckoo a fortnight for sitting and hatching 

 the eggs, and three weeks in nest for young ones 

 before they fly, and then he would give the young 

 cuckoos five or six weeks to be fed after they fly. 

 And he asserts that the cuckoos quit this country in 

 the first week of July ; which is not correct — they 

 go later, often not till August — verifying the old saw : 



"July, he may fly, 

 August, go he must." 



Dr. Bowdler Sharpe is much nearer the mark when 

 he says ("Birds," Allen's Naturalist's Library ii, p. 25), 

 " leaving about the end of July ; " for adult cuckoos in 

 sheltered situations in mild seasons are often seen in 

 the earlier days of August. 



By this kind of process you could prove or establish 

 anything ; but Jenner, though he was so far right in 

 his observations, got wrong the moment he took up a 

 theory as other clever men have done, and was deter- 

 mined to make everything bend to his plausible ex- 

 planations. 



Though it is true, as Cuvier says, that the young 

 cuckoos are " exceedingly slow in learning to take 

 their own food," yet, five or six weeks, taken up in 

 feeding the young cuckoos after they fly is too much, 

 you would by that have such a disturbance of the 

 breeding process in all victimised birds as would 

 indeed be very marked and revolutionising. Sparrows, 

 pipits and others which have three and sometimes 

 four broods a year would have only one brood or at 

 most two ; and the long drawn out periods of feeding 



