406 EVOLUTION, GENETICS, AND EUGENICS 



of a particular somatic modification. If a local poisoning had a 

 structural effect on some particular organ, and if that structural effect 

 was reproduced in any degree in the offspring, the case would be 

 relevant; but when the whole organism is soaked in a poison the case 

 is irrelevant. If it could be said that the sunshine, which brings about 

 sun-burning in the skin, soaks through the organism even to its repro- 

 ductive cells and specifically affects them, in a manner analogous to 

 the saturating poison, we should have a physiological basis for expect- 

 ing the inheritance of sun-burning. But we cannot make this assump- 

 tion. We have no warrant for believing that the modification of a 

 part re-echoes in a definite specific way through the organism until 

 even the penetralia of the germ-cells reverberate. 



2. A parent organism is poisoned, and there are structural results 

 of that poisoning. The offspring are born poisoned, and show similar 

 structural peculiarities. This may be due to the fact that the germ- 

 cells were poisoned along with the parental body; but it may also be 

 due ; in the case of a mother, to a poisoning of the embryo before birth, 

 in a manner comparable to a pre-natal infection. 



3. In some cases — e.g., of alcoholism in successive generations — 

 there may be poisoning of the germ-cells along with the body, there 

 may be poisoning of the embryo before birth, and of the infant after; 

 but it may also be that what is really inherited is a specific degeneracy 

 of nature, an innate deficiency of control, perhaps, which led the parent 

 to alcoholism, and which may find the same or some other expression 

 in the child. 



Cases are known in which the children of a dipsomaniac father and 

 a quite normal mother have exhibited a tendency to alcoholism, 

 insanity, and the like. In this case the possibility of poisoning the 

 unborn child is eliminated, but there remain three possibilities of 

 interpretation — that there was specific poisoning of the paternal germ- 

 cells; that what was inherited was the constitutional weakness which 

 expressed itself as alcoholism in the father; and that there were detri- 

 mental influences in the early nutrition, environment, education — 

 "nurture," in short — of the offspring. 



But while we have admitted a good deal, we have not admitted 

 the transmissibility of a particular structural modification brought 

 about in the parental body as a result of the toxin. 



Misunderstanding VIII. — Failure to distinguish between the 

 possible inheritance of a particular modification and the possible inheri- 

 tance of indirect results of that modification, or of changes correlated with 



