94 



PROCEEDINGS OF THE 



He did not think that the assumed stability of the genotype or 

 micTOSpecies was borne out by the results of close critical study 

 whicli often revealed micro-microspecies sometimes unrecog- 

 nizable except to the highly trained eye of the expert. 



Even granting Dr. Lotsy's hypothesis as one possible means of 

 origin of species, representing new combinations of previous 

 characters as the result of crossing, this seemed inadequate by 

 itself to account for the enormous variety of species all more or 

 less closely adapted to their environment. 



Referring to the remarkable series of Antirrhinums shown by 

 Dr. Lotsy as the result of segregation after crossing, the speaker 

 did not consider these comparable with natural species. A large 

 propoi'tion were of the nature of monstrosities, and departures 

 troin the normal in floral structure (even though very slight) would 

 militate against pollination of the flower by insect-agency and 

 thus tend towards elimination of the form. . It was important to 

 carry out the experiment of determining what would happen 

 to such a series when left to itself in nature. 



Professor MacBbide, i^.R.S. (visit07-), said that the theory so 

 ably explained by Dr. Lotsy was, in effect, exactly the same ns 

 Weismann's famous theory of heredity based on his theory of ids 

 and determinants, and the supposed different collocations of these 

 effected by the process of fertilization. 



In the logical development of his theory Weismann had to 

 account for the differences between his ids or hereditary units, 

 and to do this he had to postulate the inheritance of acquired 

 characters in the unicellular ancestors of the higher plants and 

 animal?'., and thus to give away in principle his whole case. 



Lotsy's view fails to account for the phenomena of recapitula- 

 tion in the development of animals. It we take the life-history 

 of the hermit-crab, w^e find that the larva has a symmetrical 

 abdomen, but that when the larva gives up its free-swimming life 

 and drops to the bottom it inserts its abdomen into an empty 

 univalve shell, and the abdomen becomes curved accordingly. 

 Now, if the larva be prevented from obtaining a shell its abdo- 

 men becomes curved, but not so much as when a shell is available. 

 Is it seriously suggested that the " factors " for a curved abdomen 

 were brought together by some accidental sexual union, and that 

 these factors became operative at the exact moment when the 

 larva dropped to the bottom ? 



Evidence is gradually accumulating that the environment can 

 and does affect heredity. Kammerer's work on the inheritance 

 of skin-colour in the Salamander and Agar's work on the shape of 

 the carapace in Daphnids both point in this direction. 



If tlie results obtained by these experiments are criticized as 

 wanting in clearness compared with the results obtained by 

 Mendelian crossings, it may be answered that experiments on 

 the effect of the environment are much more difficult to carry 



