TRANSACTIONS OF SECTION D. 691 



author feels that the facts furnished by the social insects strdngly favour the trans- 

 mission, through heredity, of acquired characters, both psychic and structural, but 

 that they also require other factors besides that of natural selection to explain them. 



The trouble with all theories of reproduction and heredity based solely on em- 

 bryologic and microscopic methods is, that the essence, the life principle, the 

 potential factors, must always escape such methods. Any theory that will hold 

 must cover the psychical as well as the physical facts — the total of well-established 

 experience — and this truth was recognised by Darwin in framing his tentative 

 theory of pangenesis. We are all in these matters simply discussing processes, and 

 the author believes that too much has been made of the cell theory, the cell being 

 but the medium through which assimilation, growth, organisation, regeneration, and 

 reproduction are effected by the ultimate elements and the inherited potential 

 forces, call them what we mav. The idea that the individual during its lifetime 

 develops all that is potential in the germ seems to him more philosophic than the 

 idea that the germ originates, at a specific moment of time, the tendency to all 

 that develops in the individual. It may be a perfectly correct conception, to use 

 "VVeismann's language, that the primary constituents for the characters of the 

 different forms of social insects are included in the egg, and that a particular form 

 of stimulus decides as to which group shall undergo development ; but it is diffi- 

 cult to believe, in the light of the facts which are known concerning social insects, 

 that the different kinds of ids and determinants which are thus conceived to 

 characterise the germ have not been impressed upon it as a consequence of the 

 characters, both acquired and congenital, of the parents. 



The author finally calls attention to the significant fact that just as in man, 

 among Mammalia, the higher intellectual development and social organisation are 

 found correlated with the longest period of dependent infancy ; that this helpless 

 infancy has been, in fact, a prime influence in the development, through family, 

 clan, tribe, and state, of our highest organisation and civilisation; so in the insect 

 world we find the same correlation between the highest intelligence and dependent 

 infancy, and are justified in concluding that the latter is, in the social insects as in 

 man, in the same way a prime cause of the high organisation and division of labour 

 so characteristic of them. 



4. Oti the R6le of Sex in Evolution. By John Berry Haycraft, M.D., 

 Professor of Physiology, University College, Cardiff. 



While Weismann admits that the power to vary is a property of protoplasm, 

 lie looks upon sexual conjugation as a means whereby the number of these 

 variations may be increased. But we find that the power to vary is itself a most 

 varying character of protoplasm, for both in the case of sexual and asexual 

 reproduction certain species constantly produce striking varieties, while others 

 rarely produce them. We can therefore state, not only that variation is a quality 

 of protoplasm, but that it has and can acquire this quality in varying degree and 

 apart from sexual congregation ; moreover, greater varieties in the progeny can be 

 obtained simply by increasing the number of the offspring. It would appear 

 therefore that, if we accept the view held by Weismann, we must assign to sexual 

 conjugation a function already possessed by protoplasm, and it is difl[icult to under- 

 stand its utility. If, however, we remember that the varieties which occur in 

 newly allied forms (the only ones which conjugate) are variations chiefly in quantity 

 (diflPerences iu size of the whole or parts, amount of pigment, &c.), we can hardly 

 doubt the generally accepted and more popular view, that the children tend to the 

 mean of their parents ; a view supported by Galton's admirable researches. If this be 

 true sexual conjugation tends to diminish variations, and the author suggests that this 

 is indeed the role of sex in evolution. Our attention has been so much engrossed 

 with the changes of the environment, and with the consequent production and 

 establishment of new varieties, that we have perhaps con>idered too little the fact 

 that often for long periods of time the environment may remain stationary, and 

 that under these conditions existing types must remain stable. The persistently 



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