50 
NATURE 
[Marcu II, 1915 

ducted under control in the laboratory or greenhouse 
partook too much of the nature of hospital treatment, 
and that conclusions based on such work were scien- 
tifically unsound. The open field of nature was the 
more trustworthy as the interplay of forces there had 
nothing personal in it. He could not accept the 
theory offered by De Vries and others of the origin 
of species by mutation, namely, by the inheritance 
of striking changes suddenly appearing, that is to 
say, discontinuous variations, as distinguished from 
the non-heritable fluctuations of slight degree. The 
inheritance of the discontinuous variations gives rise 
by a process of segregation to the elementary species 
of De Vries. The Darwinian species arises, on the 
contrary, by selection by an aggregation of slight 
gradual epharmonic changes. 
Dr. Rendle took as an example of the difference of 
interpretation under the two opposing views the work 
of Jordan on the Drabas and of Wettstein on alpine 
meadows. He showed no sympathy for Lotsy’s view 
of the origin of species by crossing. The resulting 
forms would be in 90 per cent. of the cases of the 
nature of monstrosities, and incapable of perpetuat- 
ing themselves. They would be too, as regards en- 
vironment, unharmonic. In conclusion, he considered 
the latest suggestion made by Prof. Bateson, that 
new forms arise by the omission of a character, to 
be full of difficulties. On this view the highest 
phase of evolution would correspond with the dis- 
appearance of all characters, while the primitive 
organisms must have been inconceivably complex. 
Prof. A. Dendy, President of Section D, considered 
that species arise by a process of fundamental evolu- 
tion, in which environment plays a leading part, and 
that the adaptations are inherited. The epigenetic 
characters are, however, modified by sexual repro- 
duction, giving permutations and combinations, fol- 
lowing Mendelian laws, which are superposed on the 
modifications due to Darwinian evolution. 
Prof. W. Bateson, President of the Association, did 
not himself attach so much importance as some of 
the speakers to the standardisation of the term 
species. He thought it hopeless to expect definite 
conclusions as to the nature and origin of species 
along the lines advocated by Dr. Rendle. 
The reason that unquestionable judgments could 
not be reached was obviously that the physiological 
nature of specific difference was still unknown. In 
the absence of this knowledge the delimitation of 
species must be arbitrary. Many, following Darwin, 
hold that the distinction between species and variety 
Was a matter of degree. That might be so, but he 
(the speaker) inclined to doubt it. No one, however, 
as yet had evidence on which a confident opinion as 
to that fundamental point could be based. Such 
evidence, if indeed attainable, could be reached only 
by physiological experiment—experiments in breeding 
providing as yet the most hopeful line. No amount 
of inspection of specimens, living or dead, could 
decide specific limits. Names must, of course, be 
given, and freely. Systematists perhaps do well to 
indicate which names they regard as prerogatively 
specific; but it should clearly be understood that 
these decisions were pragmatical and matters of con- 
venience, and they should not be offered as indica- 
tions of physiological significance. 
Prof. E. B. Poulton thought there was too much 
assumption in the distinction drawn by De Vries 
between his non-heritable fluctuations and his dis- 
continuous heritable variations as regards their herit- 
ability. He (Prof. Poulton) agreed with Prof. Dendy 
in laying stress on the importance of sexuality in 
producing new patterns by the endless combinations 
of units. He thought environment alone was not 
NO. 2367, VOL. 95] 


enough to account for the production and continu- 
ance of a variety. There must be selection too, 
Prof. Benjamin Moore caused his audience much 
amusement by stating that although he had been 
compared in the President’s address to * Harry 
Lauder’s schoolboy who took from his pocket a 
washer and said ‘that’s to mak’ a motor-car,’’ yet 
if he were starting to collect materials for building 
a motor-car he would rather begin with a washer 
than a pot of enamel paint. Workers at different 
levels on the subject of evolution were apt to despise 
one another’s work or misunderstand it. The problem 
of the origin of species, just like the problem of the 
origin of atoms, was fundamentally a_ chemical 
problem, and in its study the effects of energy trans- 
formations acting from without upon the living cell 
acting as a catalyst must be taken into account. The 
outside sources of energy formed the environment, 
and this environment acted as a directive, screening, 
and selective factor causing small variations. 
Prof. E. A. Minchin said that speaking quite 
generally and ignoring for the moment intermediate 
and transitional forms, he believed that two. principal 
grades of evolution would be recognised in the Pro- 
tista, exemplified by the Bacteria and Protozoa respec- 
tively. In the bacteria the full structure of the cell 
has not been attained, and there are no sexual pro- 
cesses. In the Protozoa, on the other hand, the 
individual is a complete and typical cell, and sexual 
phenomena occur. In the bacteria the so-called 
species are groups of individuals in which the varia- 
bility is indefinite and uncontrolled. In the Protozoa 
the variations are reduced to a common level by 
sexual blending, and fixed species occur. He believed 
that in the unicellular Protista one of the effects of 
the sexual powers is to produce true species by con-— 
trolling and levelling down variability. 
Mr. J. T. Cunningham expressed the view that 
recent discoveries concerning internal secretions or 
hormones gave evidence of a physiological process 
which would make the transmission of functionally 
produced modifications possible. 
Dr. F. A. Dixey thought that the principle of 
segregation of the gametes, especially as reinforced 
by the President’s suggestion of ‘‘ fractionation,” has 
thrown light on the persistence of some forms and 
the appearance of others. It would seem that adapta- 
tion can only be satisfactorily accounted for on the 
basis of selection applied to small inheritable varia- 
tions. 
Mis eR Ps (Gresory ands DramiGealGe 
spoke. 
Druce also 
abs lc 

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