JENNER. 69 



often an unmoved witness of this atrocity. Her whole care and 

 affection are absorbed by the intruder, and her own flesh and blood 

 literally turned out to perish. It sometimes, though very rarely, 

 happens that two cuckoo's eggs are deposited in the same nest. 

 When this occurs, and they are both hatched together, a bitter 

 feud arises, which is only terminated by the ejection of one or other 

 from the nest." 



All naturalists previous to Jenner were inclined to ascribe the 

 peculiarity in the economy of the cuckoo to its structure ; the 

 largeness of the stomach, which is only protected by a thin cover- 

 ing, they asserted, rendered the pressure attendant upon incubation 

 incompatible with health. This theory is^incorrect, and was adopted 

 without due examination. 



Jenner observes, " May they not, be owing to the following cir- 

 cumstances ? namely, the short residence this bird is allowed to 

 make in this country, where it is destined to propagate its species, 

 and the call that nature has upon it, during that short residence, to 

 produce a numerous progeny. The cuckoo's first appearance here 

 is about the middle of April. Its egg is not ready for incubation 

 till some weeks after its arrival. A fortnight is taken up by the 

 sitting bird in hatching the egg. The young bird generally con- 

 tinues three weeks in the nest before it flies, and the foster-parents 

 feed it more than five weeks after this period : so that even if a 

 cuckoo should be ready with an egg much sooner than the time 

 pointed out, not a single nestling, would be fit to provide for 

 itself, before its parent would be instinctively directed to seek 

 a new residence, and be thus compelled to abandon its young ; for 

 the old cuckoos take their final leave of this country the first week 

 in July." 



The domestic incidents of Jenner's life during this period, although 

 important to himself and his future career, were not otherwise 

 remarkable. Having experienced a disappointment in his affections 

 early in life, he continued for many years unmarried. Ultimately, 

 however, on the 6th of March, 1788, he was married to Catherine 

 Kingscote, a descendant of an ancient Gloucestershire family. 



In 1793 John Hunter died, and Jenner was deeply affected by the 

 loss of his esteemed friend. Many years previous to this sad event, 

 Jenner's anxious and affectionate attention to the symptoms of the 

 disease, which as early as 1777 had begun to attack Hunter, had 

 enabled him to detect the true nature of his illness (Angina pec- 

 toris), and the result of the examination after death fully established 

 the correctness of Jenner's views. 



In 1792, having determined to give up the general practice of his 

 profession, and practice as a physician only, Jenner obtained the 

 degree of Doctor of Medicine from St. Andrews ; and three years 

 afterwards, on finding that Berkeley by itself could never support 

 a physician, commenced making professional visits to Cheltenham, 

 a practice which he continued for many years. 



