228 GENERATION. 



The offspring being like both father and mother, shows that both 

 sexes are concerned ; that is, both have a share in the thing produced ; 

 but why the offspring is sometimes more like the one than the other 

 parent is not yet understood. Why are twins more like one another in 

 bodily appearance than other children of the same parents ? 



Influence of the male on the gestation of the female, in sexes of 

 different species or varieties. 



On September the 24th, 1782, 1 had my heifer, which was then only 

 sixteen months old, bulled by a small buffalo belonging to the Marquis 

 of Rockingham. In the month of June, 1783, she was letting down her 

 udder very fast, also her bearing [vulva] was becoming large and loose, 

 so that I expected she would calve at about the usual time, viz. nine 

 months from the copulation, which would have been about the 24th of 

 June. About this time the udder was become extremely hard, and she 

 was expected to calve every day ; but she went on till the 10th of July, 

 viz. sixteen days longer than common. By the time she had gone ten 

 days over the usual reckoning, the udder was become so turgid and so 

 hard that it appeared like the effects of inflammation, and appeared to 

 be very painful. She could hardly walk or move her hind legs ; the 

 udder, either from size, pain, or both, interfered so much with their 

 motion. 



As I had thought it probable that the buffalo -kind might either go a 

 longer or shorter time than the cow, and as mine had exceeded her time 

 ten or twelve days, I did now conceive that the buffalo went longer 

 [with calf], and that my heifer was dividing the time of her gestation 

 between that of the cow and of the buffalo. But as the operations of 

 the udder did not correspond with those of the calf and uterus as to 

 time, I began to suppose that the operations [or constitution] of the 

 calf directed those of the uterus, whilst the udder was directed by the 

 natural and original operations [or constitution] of the cow. Having 

 formed those ideas from the circumstances attending the present case, 

 I ordered the cow to be milked, and about a quart was taken away the 

 first time, and she was milked twice a day till she calved. However, 

 this was not sufficient to stop inflammation, and she was like to lose 

 one pap. 



Relation of size of offspring to number produced and mode of 

 development. 



The [new-born] young of animals do not always bear the same size 

 in proportion with that of the parent. This, in some degree, depends 



