106 THE NEW PHYSIOLOGY. 



i 



organism or only a germ-cell, separates off part of its 

 structure ; and this portion grows, and may divide 

 again and again before the first organism is reproduced. 

 Moreover, the process of growth, division, and final 

 reproduction is capable of indefinite repetition, and in 

 ordinary cases two separate organisms — the male and 

 female — combine in the process, and both contribute 

 in the hereditary transmission of character. It thus 

 appears, firstly, that a part, and usually a microscopically 

 minute part, is capable of reproducing the whole : 

 secondly, that each such minute part can reproduce 

 itself indefinitely, and even combine in doing so with 

 other minute parts from another organism. 



The mechanistic hypothesis from which we started 

 was that the characteristic properties of the whole 

 organism are due to the arrangement of its separate 

 constituent parts, be they single molecules or aggregates 

 of molecules. But in reproduction the body separates 

 off one of its parts, in which part, of course, the arrange- 

 ment present in the whole cannot be contained. This 

 part then proceeds to build up the structure again, and 

 may repeat the process indefinitely. If this had been 

 a laboratory experiment specially designed to answer the 

 question whether the behaviour of an organism depends 

 simply on the arrangement of its parts, no more con- 

 clusive negative result could have been imagined : for 

 when the arrangement is taken away the behaviour never- 

 theless returns to what it was. 



In the process of reproduction the whole structure, 

 it is true, is not discarded. Certain minute parts are 

 at first preserved intact. But these parts, too, must 

 divide and grow, to provide for future germ-cells. Thus 



