Review. 
207 
of the A -type, and d fortiori if the grandparent were also, and so 
forth, the germ cells of the ^-individual would much more cer¬ 
tainly be of the type his somatic characters would lead one to 
•expect. 
These considerations will, I believe, be useful in considering 
Mendel’s Laws themselves, and their relation to the Law of 
Ancestral Heredity. I have, I hope, said enough to shew the 
reader that however the two may be related they cannot at least be 
■“ absolutely inconsistent ” with each other, as Mr. Bateson contends. 
The law of ancestral heredity is certainly a law of nature of wide 
generality which cannot be dismissed in such a fashion. Mendel’s 
Laws I assume to be true also. The problem is to delimit their 
respective spheres, and shew in what way the one type of law may 
pass into the other, or the two even coexist. 
(to be continued.) 
REVIEW. 
The Structure and Development of the Stem in the Pteridophyta and 
Gymnosperms. By E. C. Jeffrey, Ph.D., Phil. Trans. Roy. Soc., B. Vol. 195, 
pp. 119-146, plates 1-6, 1902. 
T HE recent appointment of the author of this memoir to a 
Professorship at Harvard will be welcomed by his friends in 
this country, though they may feel some regret at the secession 
from the ranks of British men of science, of so able and energetic 
a botanist. 
In the present communication, Professor Jeffrey completes the 
Trilogy of memoirs in which he has developed the theory first 
suggested in preliminary notices, in 1896 and 1897. The Equisetales 
and the Angiosperms having been already dealt with, the remaining 
classes of vascular plants (Filicales, Lycopodiales and Gymno"] 
sperms) are now considered, and the theoretical conclusions which 
the author draws from his extensive observations are finally stated. 
Professor Jeffrey begins by suggesting a comparison, from the 
point of view of taxonomic importance, between the osseous skeleton 
