24 SCIENCE PROGRESS 



young organism at a very early stage, but in Plants they are 

 separated at a much later date from the less isolated embryonic 

 regions that provide for the Plant's branching. In all cases 

 we find embryonic and germ-cells screened from the life pro- 

 cesses of the complex organism, or taking no very obvious 

 part in it, save to form new tissues or new organs, notably 

 in Plants. 



Again, in ourselves and to a greater or less extent in all 

 Animals, we find a system of special tissues set apart for the 

 reception and storage of impressions from the outer world and 

 for guiding the other organs in their appropriate responses — 

 the " Nervous System"; and when this system is ill-developed 

 or out of gear the remaining organs work badly from lack 

 of proper skilled guidance and co-ordination. How can we, 

 then, speak of " memory " in a germ-cell which has been 

 screened from the experiences of the organism, which is too 

 simple in structure to realise them if it were exposed to 

 them ? My own answer is that we cannot form any theory 

 on the subject. The only question is whether we have any 

 right to infer this " memory " from the behaviour of living 

 beings ; and Butler, like Hering, Haeckel and some more 

 modern authors, has shown that the inference is a very strong 

 presumption. Again, it is easy to over-value such complex 

 instruments as we possess. The possessor of an up-to-date 

 camera, well instructed in the function and manipulation of 

 every part but ignorant of all optics save a hand-to-mouth 

 knowledge of the properties of his own lens, might say that 

 a priori no picture could be taken with a cigar-box perforated 

 by a pin-hole ; and our ignorance of the mechanism of the 

 psychology of any organism is greater by many times than 

 that of my supposed photographer. We know that Plants are 

 able to do many things that can only be accounted for by 

 ascribing to them a '* psyche," and these co-ordinated enough 

 to satisfy their needs ; and yet they possess no such central 

 organ comparable to the brain, no highly specialised system 

 for intercommunication like our nerve trunks and fibres. As 

 Oscar Hertwig says, we are as ignorant of the mechanism of 

 the development of the individual as we are of that of hereditary 

 transmission of acquired characters, and the absence of such 

 mechanism in either case is no reason for rejecting the proven 

 fact. 



