ZOOLOGY AND BOTANY. MICROSCOPY, ETC. 
193 
Lines of Variation and Germinal Selection.* — Prof. C. Emery 
emphasises the importance of Weismann’s recent essay on Germinal 
Selection. A new departure may be due to germinal selection alone ; 
personal selection will not influence its origin ; there may be a conflict 
between germinal and personal selection, as when a strong new character 
exceeds the optimum. Emery does not agree with Weismann that all 
organic structure is adaptive ; many characters appear to him to be 
quite indifferent. Nor does he admit the necessity of assuming an un- 
failing supply of fit variations ; the extinction of races is eloquent proof 
of the reverse. He also points out that if an environmental change 
(e.g. of climate) influenced not only the body, but the determinants of 
the germ-plasm as well ; and if it influenced not a fraction of similar 
determinants (which might lead to germinal struggle between the 
changed and the unchanged), but influenced all alike ; and if the same 
factor operated for several generations ; and if the resulting change was 
indifferent, i.e. without selection-value ; then there is a logical possibility 
of the origin of a character without any selection. 
Organic Selection.! — Prof. J. Mark Baldwin uses this phrase, which 
can hardly be called self-explanatory, to express “ the perpetuation and 
development of congenital coincident variations in consequence of accom- 
modation.” By “ accommodation ” is here meant an adaptive reaction 
of the organism to its environment, which may result in a “ modifica- 
tion.” The idea is that congenital variations coincident or in the same 
line with adaptive modifications, are screened by the modifications, and 
thus indirectly selected. (Perhaps “ indirect selection ” might be sug- 
gested instead of “ organic selection.”) The results of organic selection 
are included under the term ortlioplasy, which has, however, a wider con- 
notation. Prof. Baldwin’s contribution contains other suggestions to- 
wards a more definite terminology. 
Study in Variation.^ — Mr. H. C. Bumpus has used X-rays in the 
investigation of the variations which occur in the vertebral column of 
Necturus maculatus Raf. A hundred specimens were examined. There is 
an average of 35 per cent, of liomoeotic variation, i.e. where a .vertebra, for 
instance, assumes a structure which is proper to another in a different 
ordinal position in the series. These variations are all in the pelvic 
region. There is also considerable meristic variation, i.e. in the total 
number of segments in the column. The two forms of variation are as- 
sociated; for specimens with abnormally placed sacra (homoeotic) present 
-a considerably increased meristic variation ; and extremes in meristic 
vertebral variation tend towards homoeosis. There is a ratio between 
the absolute length of the animal and the number of vertebras. Some 
suggestions are made to show that forward homoeosis is, so to speak, 
easier than backward homoeosis, which is less frequent. 
The author maintains that the differentiation of the sacral vertebra is 
the result of centripetal influence from the growing Anlage of the appen- 
dage, whose primitive position may readily vary a little, thus inducing 
an unsymmetrical sacrum. Pie argues that the appendage appears at a 
definite topographical point, without respect to the location of certain 
* Biol. Centralbl., xvii. (1897) pp. 142-6. f Nature, Iv. (1897) p. 558. 
t Journ. Morphol., xii. (1897) pp. 455-84 (8 pis.). 
