386 THE GERM-PLASM 



immediate fertilisation of the latter is rendered inconceivable 

 by the fact of their immaturity, and the sperm-cell must have 

 remained in the body of the ovum until the maturation of the 

 latter, with the nucleus of which it then united in the process of 

 amphimixis. If this occurred sometime after the first of the 

 offspring was born, it might easily have coincided approximately 

 with the second coitus, from which the fertilisation would then 

 apparently be due. If the 'infection' were proved beyond a 

 doubt, a supplementary fertilisation of an egg-cell in this 

 manner must be considered possible ; we certainly might then 

 reasonably ask why mares, cows, or sheep, should not occa- 

 sionally become pregnant without being covered a second time. 

 But this has never yet been k7iown to occur, and I incline to 

 Settegast's view that there is no such thing as an ' infection ' of 

 this kind, and that all the instances which have been recorded 

 and discussed critically by him are based upon a misconception. 



2. The Influence of Temporary Abnormal Conditions 

 OF THE Parents on the Child 



Although I do not consider that the cases which come under 

 the above heading have anything to do with heredity, I should 

 not like to leave them entirely on one side. 



It has often been supposed that drunkenness of the parents at 

 the time of conception may have harmful effect on the nature of 

 the offspring. The child is said to be born in a weak bodily 

 and mental condition, and inclined to idiocy, or even to mad- 

 ness, &c., although the parents may be quite normal both 

 physically and mentally. 



Cases certainly exist in which drunken parents have given 

 rise to a completely normal child, although this is not a con- 

 vincing proof against the above-named view ; and in spite of 

 the fact that most, or perhaps even all, the statements with 

 regard to the injurious effects on the offspring will not bear a 

 very close criticism, I am unwilling to entirely deny the possi- 

 bility that a harmful influence may be exerted in such cases. 

 These, however, have nothing to do with heredity, but are 

 concerned with an affection of the germ by means of an external 

 influence. 



The experiments of the brothers Hertwig show that the develop- 

 ment of the fertilised egg in lower animals may be considerably 



