108 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
“A part is not only nourished but also actively nourishes itself, and 
the more vigorously, the more powerful and capable of assimilation it is. 
Hence powerful determinants in the germ will absorb nutriment more 
rapidly than weaker determinants. The latter, accordingly, will grow 
more slowly, and will produce weaker descendants than the former.” 
“ Minus variations repose on the weaker determinants of the germ, 
that is, on such as absorb nutriment less powerfully than the rest. And 
since every determinant battles stoutly with its neighbours for food, that 
is, takes to itself as much of it as it can, consonantly with its power of 
assimilation and proportionately to the nutrient supply, therefore the 
unimpoverished neighbours of this minus determinant will deprive it of 
its nutriment more rapidly than was the case with its more robust 
ancestors ; hence it will be unable to obtain the full quantum of food 
corresponding even to its weakened capacity of assimilation, and the 
result will be that its descendants [“ ancestors ” in the translation] will be 
weakened still more. 
“As soon as personal [individual] selection favours the more power- 
ful variations of a determinant, the moment that these come to predomi- 
nate in the germ-plasm of the species, at once the tendency must arise for 
them to vary still more strongly in the plus direction, not solely because 
the zero-point has been pushed further upwards, but because they them- 
selves now oppose a relatively more powerful front to their neighbours, 
that is, actively absorb more nutriment, and upon the whole increase in 
vigour and produce more robust descendants. From the relative vigour 
or dynamic status of the particles of the germ-plasm, thus, will 
issue spontaneously an ascending line of variation, precisely as the facts 
of evolution require.” 
“ Thus, I think, may be explained how personal selection imparts 
the initial impulse to processes in the germ-plasm, which, when they are 
once set agoing, persist of themselves in the same direction, and are 
therefore in no need of the continued supplementary help of personal 
selection, as directed exclusively to a definite part.” 
There is much else in the essay which deserves careful attention, — 
the general vindication of the selection-principle, the modification of his 
theory of panmixia, the apology for hypotheses, and so on, but in our 
limited space we have thought it better to give prominence to the main 
idea. 
Evolution on Definite Lines.* — Prof. G. II. Th. Eimer delivered a 
lecture on this subject at the International Congress in Leyden, which 
may be fitly noticed in connection with Weismann’s. Two more anti- 
thetic utterances it is difficult to conceive. 
Orthogenesis, or progressive variation in definite direction, is a fact : 
and a fact destructive to Darwinism. 
The causes of orthogenesis are to be found in the action of environ- 
ment upon the constitution of the organism. Evolution is a larger 
aspect of growth. 
The facts of orthogenesis lead us to recognise certain laws of 
evolution, of which Eimer states ten, as in his book. 
The origin of species depends not on selection, but (1) on stoppage 
(Genepistasis) at given stages in the evolution-process, (2) on saltatory 
* CK. Internat. Congr., 1896, pp. 145-69. 
