AUEMST) 125.1015) 
NATURE 
657 

ticity of the strophanthinised heart; and Prof. P. T. 
Herring on the effect of thyroidectomy on the adrenin- 
content of the suprarenals. 
In Section K a lecture is to be given by W. 
Lawrence Balls on cotton, and the following papers 
will be read :—Prof. F. O. Bower on the evolution of 
some ferns, in particular the Dipterids and the allies 
of the common bracken; Dr. D. H. Scott on the 
fossil plants of the genus Heterangium; Dr. Marie C. 
Stopes on the fossils of the Aptian (Greensand) period, 
including some of the oldest flowering plants of this 
country showing internal structure; Prof. Osborn on 
the morphology of Selaginella uliginosa, and his wife 
on some Australian fossils belonging to the genus 
Zygopteris; Dr. Ellis on fossil bacteria and fossil 
fungi; Dr. Sarah M. Baker on a new hypothesis 
regarding the ascent of sap in plants; Dr. Marion 
Delf on the effect of temperature on the permeability 
of protoplasm to water; Miss Prankerd on Statoliths ; 
Prof. W. B. Bottomley on the formation of auximones 
from nitrogenous organic substances; Prof. Julius 
MacLeod on the expression by measurements of specific 
characters with special reference to the mosses; Dr. 
J. C. Willis on the evolution of the flora of Ceylon. 
In Section L the following discussions may be 
expected :—On methods and content of history as a 
subject of school study; on military training in 
schools; on education of women in relation to their 
careers; on education and industry. 
In Section M papers will be read by Prof. J. 
Hendrick on composition and uses of seaweed; by 
Prof. W. Somerville on accumulation of fertility in 
grass land; by D. Macpherson on types of hill graz- 
ings, their economic value and importance; and dis- 
cussions will take place on probable effects of the war 
on the future of British agriculture, and the economics 
of mill production. 

END) WSINOLD NA ONE | JVB IROID IMI 
Tp popularity of problems of genetics as subjects 
for research and discussion is well illustrated by 
the May number of the American Naturalist (vol. xlix., 
No. 581), every paper in which bears on one or other 
of such problems. Of especial interest is Prof. Jacques 
Loeb’s article on the nature of the conditions which 
determine or prevent the entrance of the spermatozoon 
into the egg. It is well-known that in normal ter- 
tilisation, the entrance of the spermatozoon is followed 
by the formation of a membrane around the egg, so 
that the entrance of other spermatozoa is prevented. 
But, as Prof. Loeb has already recorded in his worl: 
on ‘Artificial Parthenogenesis and Fertilisation,’’ sea- 
urchin eggs the development of which has been started 
by treatment with hypertonic sea-water can be after- 
wards fertilised, a spermatozoon being capable of 
entering a blastomere—at least up to the stage of the 
eighth cleavage—and inducing ‘‘a distinct and clear 
membrane formation’’ around it. This shows that the 
entrance of a male cell is not necessarily prevented by 
“the changes underlying development.’” But eggs by 
treatment with butyric acid can be induced to form 
a membrane. If this membrane remain unbroken 
subsequent fertilisation becomes impossible, though 
parthenogenetic segmentation may begin; if, however, 
the membrane be ruptured by shaking, a spermatozoon 
can enter and the egg undergoes normal development. 
Hence it may be inferred that the physical condition 
of the surface of the egg—howsoever modified—is the 
immediate determinant of the admission or exclusion 
of a spermatozoon. This view is supported by Loeb’s 
experiments in cross-fertilisation, which show that the 
sea-urchin (Strongylocentrotus) egg admits the sperm 
of an echinoderm of another class only in a hyper- 
NO. 2389, VOL. 95| 
| menters. 


alkaline solution. On the other hand, eggs cannot be 
fertilised by sperms of their own species in sea-water 
containing an excess of neutral chlorides. From all 
these facts Loeb is inclined to draw the conclusion 
that the tension of the surface of the egg may explain 
the engulfment or exclusion of the spermatozoon. But 
it is obvious that in the case of normal fertilisation 
this surface-condition is ‘‘induced from within the egg 
by changes caused by the entrance of the spermato- 
zoon’’—a deduction made by biologists long before 
the study of ‘‘experimental embryology ’’ had become 
fashionable. 
In the same number of the American Naturalist Dr. 
Raymond Pearl continues his studies in heredity with 
reference to questions of practical breeding with a 
paper on Mendelian inheritance of fecundity in the 
domestic fowl.’ Large egg-yield, especially during 
the winter months, is shown by experiment to depend 
upon the presence of two Mendelian factors in the 
germ-cells, so linked with sex-determining characters 
that the female is heterozygous. Thus is confirmed 
the belief of some poultry-fanciers that the father is of 
greater importance than the mother for the establish- 
ment of a ‘good laying strain.’”’ In the Biological 
Bulletin (vol. xxviii., No. 3) Dr. M. R. Curtis describes 
a Rhode Island red hen with the terminal part of her 
oviduct aborted. Consequently the eggs—-which were 
produced in the normal way—passed out into the body 
cavity and their food materials were absorbed by the 
bird’s tissues without disturbance of the metabolism. 
A recent number of our British Journal of Genetics 
| (vol. iv., No. 4) contains a noteworthy paper, by Dr. 
H. Drinkwater, on the inheritance of brachydactyly in 
human families. The observations on this condition 
made by Dr. W. C. Farabee in North America, and 
by Dr. Drinkwater in this country are summarised in 
Mr. Bateson’s book, ‘‘ Mendel’s Principles of Heredity,” 
and brachydactyly has become a classical example of a 
simple Mendelian dominant-character. Dr. Drinkwater 
now describes a second family in England, and proves 
it to be a branch of the American stock studied by 
Dr. Farabee. The most important feature of the 
present study is found in the very beautiful series of 
radiographs of the brachydactylous hands and feet. 
The second phalanx is not really absent, but remains 
in a rudimentary condition, and becomes usually united 
to the base of the terminal phalanx. 
Colour phenomena in animal and plant inheritance 
naturally continue to attract the attention of experi- 
A short paper on the ‘‘ English” rabbit, by 
Prof. W. E. Castle and P. B. Hadley (Proc. Nat. 
Acad. Sci., vol. i.) is worthy of note. The ‘‘standard” 
coat in these rabbits is white with black muzzle, ears, 
and spots on back and flanks. Breeding experiments 
have shown that this ‘‘standard” coloration is really 
a mark of hybridity, for when mated together such 
rabbits yield a progeny half of which are either with- 
out the back and flank black markings or with these 
greatly exaggerated. The present paper describes how 
a ‘‘standard English’’ buck was mated with ‘‘ Belgian 
hare’? does, and how one of his dark-coated sons 
from this cross was afterwards mated to the same 
does; the result was that this latter begot distinctly 
darker offspring than his father, the ‘‘modal grades” 
being respectively 2:0 and 3:25. ‘Yet the father,” 
write the authors, ‘‘contained only a single dose (one 
gamete) of English pattern, and the son derived his 
English pattern exclusively from this same source. 
Hence the English unit-character had changed quan- 
titatively in transmission from father to son. This 
seems to us conclusive evidence against the idea of 
unit-character constancy or gametic purity.” 
Dr. L. J. Cole’s paper on the inheritance of colour 
in pigeons (Rhode Island Agric. Exp. Station, Bulletin 
158) was summarised in NaTure last year (vol. xciv., 
