Geology and Natural History. 223 
Pfeffer’s Vegetable Physiology is a masterly treatise. It pre- 
sents In sys ic form, and with references throughout, a 
r 
of nitrogenous compounds within the plant, a subject to which 
Pfeffer has devoted much time, is treated pretty fully but is not 
tion, especially that which is known as “ intra-molecular,” so ex- 
tensively presented as it appears to deserve. In the second vol- 
ume, the release of energy is discussed under growth, movement, 
and the production of light, heat and electricity. Nearly every 
page exhibits personal familiarity with the phenomena described 
and not merely with the literature. The propositions are every- 
where well presented, but the arguments in support 0 them are 
as clearly put. Part of the fault comes no doubt 
from the unwillingness to place headings at the proper places 
his publishers to 
prepare a fifth edition of his text-book, but he felt so much un- 
satisti e systematic portion is turned over ost pr 
ising young professor who has recently established himself at 
Rostock, an work -has already appeared under Goebel’s 
name and with Sachs’s sanction. 2 
been wholly recast, and is now published as a series of forty-s 
lectures, Tt may be said at the outset, that the lectures are in- 
