628 TRANSACTIONS OV SECTION D. 



raises the expectation that a chemical bond must exist between the functionally 

 active organs of the body and the germ-cells. For if, in the absence of a 

 specialised nervous system, the only possible regulating and coadapting mechanism 

 is a chemical mechanism, and if the specific activities of a cell are dependent on the 

 enzymes which it holds in combination, the germ-cells of any given animal must 

 be the depository of a stock of enzymes sufficient to insure the due succession of all 

 its developmental stages as well as of its adult structure and functions. And as the 

 number of blastomeres increases, and the need for co-ordination of form and func- 

 tion arises, before ever the rudiments of a nervous system are differentiated, it is 

 necessary to assume that there is also a stock of appropriate hormones to supply 

 the chemical nexus between the different parts of the embryo. The only alterna- 

 tive is to suppose that they are synthesised as required in the course of develop- 

 ment. There are grave objections to this supposition. All the evidence at our 

 disposal goes to show that the potentialities of germ-cells are determined at the 

 close of the maturation divisions. Following the physiological line of argument, 

 it must, be allowed that in this connection ' potentiality ' can mean nothing else 

 than chemical constitution. If we admit this, we admit the validity of the theory 

 advanced by more than one physiologist that heritable ' characters ' or ' ten- 

 dencies ' must be identified with the enzymes carried in the germ- cells. If this 

 be a true representation of the facts, and if the most fundamental and primitive 

 bond between one part of an organism and another is a chemical bond, it can 

 hardly be the case that germ-cells — which, inter alia, are the most primitive, in 

 the sense of being the least differentiated, cells in the body — should be the only 

 cells which are exempt from the chemical influences which go to make up the 

 co-ordinate life of the organism. It would seem, therefore, that there is some 

 theoretical justification for the inheritance of induced modifications, provided 

 that these are of such a kind as to react chemically on the enzymes contained in 

 the germ-cells. 



One further idea that suggests itself to me and I have done. Is it possible 

 that different kinds of enzymes exercise an inhibiting influence on one another ; 

 that germ-cells are ' undifferentiated ' because they contain a large number of 

 enzymes, none of which can show their activities in the presence of others, and 

 {hat what we call ' differentiation ' consists in the segregation of the different 

 kinds inio separate cells, or perhaps, prior to cell-formation, into different parts 

 of the fertilised ovum, giving rise to the phenomenon known to us as prelocalisa- 

 tion? The idea is purely speculative; but, if it could be shown to have any 

 warrant, it would go far to assist us in getting an understanding of the laws of 

 the production of form. 



I have been wandering in territories outside my own province, and I shall 

 certainly be told that I have lost my way. But my thesis has been that mor- 

 phology, if it is to make useful progress, must come out of its reserves and explore 

 new ground. To explore is to tread unknown paths, and one is likely to lose 

 one's way in the unknown. To stay at home in the environment of familiar 

 ideas is no doubt a safe course, but it does not make for advancement. Morpho- 

 logy, I believe, has as great a future before it as it has a past behind it, but it 

 can only realise that future by leaving its old home, with all its comfortable 

 furniture of well-worn rules and methods, and embarking on a journey, the first 

 stages of which will certainly be uncomfortable and the end is far to seek. 



FBI DAY, SEPTEMBER 2. 



Joint Meeting with Section K. 

 The following Papers were read : — ■ 

 1. The New Force, Mitokinetism. By Professor Marcus Hartog, D.Sc. 



On the discovery of the cell-field in karyokinesis its analogy with that of 

 two opposite magnetic or electric poles was 'at once recognised. This analogy 

 was developed towards the beginning of the present century, especially by Reinke, 

 Ziegler, and Gallardo. A little later it fell to the author to complete the gaps 



