114 



PROF. ERNEST W. MACBRIDE, M.A., F.R.S., ON 



Morgan's Introduction, pp. 47, 48, The German War-Bool:. London : 

 John Murray, 1915.) 



The Key. M. Davidson asked whether Professor MacBride thought 

 that fortuitous variations were partly due to bisexual reproduction. 

 Weismann himself discovered that two varieties of Cypris reptans 

 possessing marked colorations occur in the ponds near Freiburg. 

 Individuals of the dark green variety appeared suddenly in an 

 aquarium which' contained the yellow-ochre coloured variety in the 

 year 1887. As these variations occurred in the absence of sexual 

 reproduction, this cannot be the sole cause of variations. 



Would it be possible to ascribe fortuitous variations, if not due to 

 bisexual reproduction, to the tendency of the cell to divide 

 unequally, since the probability of the cell dividing equally would 

 be very small, so that cells would tend to become heterogeneous 1 



Further, do regressive variations play any part in the evolution 

 of species or varieties 1 He believed that Keid in his works had 

 strongly emphasized that, without regressive variation, all species 

 would rush to destruction. By regressive variation was meant failure 

 to recapitulate ancestral development. 



The Eev. J. J. B. Coles felt sure that they were all much obliged 

 to Professor MacBride for having come and put before the Institute a 

 statement, quite up-to-date, of the position of a theory of this import- 

 ance. They were equally indebted to him for the way in which he 

 presented the statement, and for the scientific honesty and caution 

 which allowed that, on several very difficult points, no true solution 

 had yet been attained. 



The real problem of biology Mas the origin of diversity. That 

 problem was yet unsolved. Might he suggest that in organic beings 

 an element was found that was not automatic. We were not 

 automata ourselves, but had a certain freedom of choice, and the same 

 was the case with animals. To carry the argument further, was not 

 an independent means of organic action found in the lower forms 

 of life ? If so, the question was one which called for a fuller investi- 

 gation than it had yet received, as it ran on the true lines of 

 comparative science. He thought, therefore, that in all organic- 

 matter, where we had life and all its mystery, it was better to begin 

 at the very commencement, and to believe that in the primordial germ 

 there was the beginning of that which might lead to some form of 

 variation. 



