394 



SCIENCE 



[N. S. VoL.XXVni. No. 717 



suits are concerned, 'the external stimulus. 

 Thus, if a somatic cell (A) is induced by 

 an external stimulus (S) acting on the 

 nucleus to assume a new manner of de- 

 velopment, a disturbance spreads through 

 the organism, so that finally the nuclei 

 of the germ-cells are altered in a similar 

 manner. When the cellular descendants 

 of the germ-cells reach the same stage of 

 ontogeny as that in which the original 

 stimulation occurred, a stimulus comes 

 into action equivalent to S as regards the 

 results it is capable of producing. So 

 that the change originally Avrought in cell 

 A by the actual stimulus S is now re- 

 produced by what may be called an inher- 

 ited stimulus. But when A was originally 

 affected other cells, B, C, D, may have re- 

 acted to S by various forms of growth. 

 And therefore when during the develop- 

 ment of the altered germ-cell something 

 equivalent to S comes intO' play, there will 

 be induced, not merely the original change 

 in the development of A, but also the 

 changes which were originally induced in 

 the growth of B, C, D. Thus, according 

 to Rignano, the germ-nucleus releases a 

 number of developmental processes, each 

 of which would, according to Weismann, 

 require a separate determinant. 



If the view here given is accepted, we 

 must take a new view of Weismann 's 

 eases of simultaneous stimulation, i. e., 

 cases like Fischer's experiments on Arctia 

 caja, which he does not allow to be so- 

 matic inheritance. If we are right in say- 

 ing that, the original excitation of the 

 soma is transferred to the germ-cell, and 

 it does not matter whether the stimu- 

 lus is transferred by "telegraphy," or 

 whether a given cause, e. g., a low temper- 

 ature, acts simultaneously on soma and 

 germ-cell. In both cases we have a given 

 alteration produced in the nuclei of the 

 soma and the germ-cell. Nageli used the 

 word telegraphy to mean a dynamic form 



of transference, but he did not exclude the 

 possibility of the same effect being pro- 

 duced by the movement of chemical sub- 

 stances, and went so far as to suggest that 

 the sieve tubes might convey such stimuli 

 in plants. In any case this point of view^^ 

 deserves careful consideration. 



Still another code of communication 

 seems to me to be at least conceivable. 

 One of the most obvious characteristics of 

 animal life is the guidance of the organ- 

 ism by certain groups of stimuli, produ- 

 cing either a movement of seeking (posi- 

 tive reaction--) or one of avoidance 

 (negative reaction). Taking the latter as 

 being the simplest, we find that in the low- 

 est as in the highest organisms a given 

 reaction follows e-ach one of a number of 

 diverse conditions which have nothing in 

 common save that they are broadly harm- 

 ful in character. We withdraw our 

 hands from a heated body, a prick, a cor- 

 rosive substance, or an electric shock. 

 The interesting point is that it is left to 

 the organism to discover by the method of 

 trial and error the best means of dealing 

 with a sub-injurious stimulus. May we 

 not therefore say that the existence of 

 pleasure and pain simplifies inheritance? 

 It certainly renders unnecessary a great 

 deal of detailed inheritance. The innum- 

 erable appropriate movements performed 

 by animals are broadly the same as those 

 of their parents, but they are not neces- 

 sarily inherited in every detail; they are 

 rather the unavoidable outcome of hered- 

 itary but unspecialized sensitiveness. It 

 is as though heredity were arranged on a 

 code-system instead of by separate signals 

 for every movement of the organism. 



It may be said that in individual life 

 the penalty of failure is pain, but that the 



^ See Semon, Archiv f. Bassen- und Gesell- 

 schafts-Biologie, 1907, p. 39. 



^ See Jennings, " Behavior of the Lower Organ- 



