TRANSMISSIBILITY OF FUNCTIONAL MODIFICATIONS 69 



as was done, for instance, by M. Nussbaum, who cited as a proof of 

 this the migration of the alga-cells which live in the endoderm of the 

 green freshwater Hydra into the ovum, which is originally colourless, 

 and originates in the ectoderm of the animal (Fig. 35 5, p. 169, vol. i). 

 It seems to me better to make a precise distinction between the trans- 

 mission of exti^aneous micro-organisms through the germ-cells and the 

 handing on of the germ-plasm with the characters inherent in its 

 structure. Only the latter is inheritance in the strict scientific sense, 

 the former is infection of the germ. 



Still less than the cases of inherited traumatic epilepsy can the 

 morbid constitution of the children of drunkards be. regarded as a 

 proof of the inheritance of somatogenic characters, though this has 

 often been maintained. I will not lay any stress on the fact that the 

 allegation itself is, according to the most competent observers, such as 

 Dr. Thomas Morton ^, far from being estaljlished. But even if it 

 were quite certain that the numerous diseases of the nervous system, 

 amounting sometimes to mania, which are frequently observed in the 

 children of drunkards, were really caused by the drinking of the 

 parents, it ought not to be overlooked that we have here to do not 

 with the hereditary transmission of somatic variations, but of varia- 

 tions directly induced in the germ-plasm of the reproductive cells, for 

 these are exposed to the influence of the alcohol circulating in the 

 blood, just as any other part of the body is. That l^y this means 

 variations in the germ-plasm can be brought about, and that these 

 may lead to morbid conditions in the chiklren cannot be denied, and 

 ought not on a priori grounds to be called in question. For we are 

 acquainted with many other influences — climatic, for instance — 

 which directly aflect and cause variation in the germ-plasm. Whether 

 this is so in the case of drunkenness, and in what manner it comes 

 about, whether through direct action of the alcohol, or through 

 infection of the germ with some microbe, we must leave to the 

 future to decide ; the whole question is out of place here ; it can in no 

 way help us to clear up the problem with which we are now occupied. 



But even if there were not a trace of proof of the transmissibility 

 of functional modifications, that alone would not justify us in con- 

 cluding that the transmission is impossible, for many things may 

 happen that we are not in a position to prove at present. If it could 

 be shown that there was a whole group of phenomena that could not 

 be explained in any other way than on the hypothesis of such 

 inheritance, then we should be obliged to assume that it really 



^ Morton. ' The Problem of Heredity in Reference to Inebi'iety,' Proceed. Soc. for 

 the Study of Inebriety, No. 42, Nov. 1894. 



