7Q INHERITANCE 



Chap. XIV 



grown plants differ but little. Cabbages on the other hand diff 

 greatly in foliage and manner of growth, but hardly at aQ •* 

 their seeds ; and generally it will be found that the difference 11 

 between cultivated plants at different periods of growth are not 



ily closely connected together, for plant 



& 



t . , . ., - j. ' mav differ 



much m their seeds and little when full-grown, and conversely 



may yield seeds hardly distinguishable, yet differ much when full- 

 grown. In the several breeds of poultry, descended from a sin 

 species, differences in the eggs and chickens, in the plumage 

 the first and subsequent moults, in the comb and wattles dur 

 maturity, are all inherited. With man peculiarities in the n 

 and second teeth, of which I have received the details, ir- 

 ritable, and with man longevity is often transmitted. ' 





improved breeds of 



So ag 



and sheep, early maturity, 

 including the early development of the teeth, and with certain 

 breeds of fowl the early appearance of secondary sexual cha- 

 racters, all come under the same head of inheritance at 

 corresponding periods. 



Numerous analogous facts could be given. The silk-moth 

 perhaps, offers the best instance; for in the breeds which 

 transmit their characters truly, the eggs differ in size, coW 

 and shape ;-the caterpillars differ, in moulting three or 

 times, in colour, even in having a dark-coloured mark like an 

 eyebrow, and in the loss of certain instincts ;— the cocoons differ 

 in size, shape, and in the colour and quality of the silk ; these 

 several differences being followed by slight or barely distin- 

 guishable differences in the mature moth. 



may be said that, if in the above cases a new pecu- 



fou 



But 



liarity is inherited, it must be at the 



ponding stage of 



development; for an egg or seed can resemble only an egg 

 seed, and the horn in a full-grown ox can resemble only a horn. 

 The following cases show inheritance at corresponding periods 

 more plainly, because they refer to peculiarities which might 

 have supervened, as far as we can see, earlier or later in life, 

 yet are inherited at the same period at which they first ap- 



pe 



In the Lambert family the porcupine-like excrescences appeared in 

 the lather and sons at the same age, namely, about nine weeks after 



