534 BOTANICAL GAZETTE [JUNE 
evidence that the living cells of the organism are sutrounded by semipermeable 
membranes with a difference in electrical potential outside and inside the 
membrane, and that any stimulus causes an increase of permeability with its 
necessary contractile and electrical effects. Again, the behavior of colloids 
in the form of gels leads one to believe that hydration-changes accompany 
response to stimuli in the protoplasm, which always involve contractile and 
electrical effects. These are probably the physical factors entering into Bosr’s 
Bae oe response and conduction. With death (coagulation of the 
—— e membranes and the colloids disappear, and with them the 
ee response. 
Many statements in the book show a lack of familiarity with the anatomy 
sail physiology of plants. The author speaks repeatedly of depleted energy 
in the pulvinus of Desmodium, or of its receiving energy from without. This 
is rather vague in the light of what we know of the energy relations of plants. 
He applies systole and diastole to the pulvinus as he does to the heart, and 
compares the petiole of Mimosa with the nerve and the pulvinus with the 
muscle of a nerve muscle preparation. Both of these statements are made in 
spite of the fundamental differences in structure and function. The death 
point for plant cells is fixed, as if mysteriously, at 60° C., and death from a 
lower temperature is spoken of as being very different in nature. Bose fails 
to recognize that death at supramaximal temperatures is a matter of coagula- 
tion of certain proteins, and that at any supramaximal temperature the time 
of its application is a function in the process. At temperatures lower than 60° 
C. the time must be longer. The reason that 60° C., rather than a lower or 
higher temperature, is found to be the death temperature in a given species, is 
because of his method of heating, namely, 1° C. rise in temperature per minute. 
A slower heating would give a lower death gil and a faster one a higher ome 
The reason for the constancy of this t for the different ies stud 
is not so clear. Bose should have been acquainted with LEPESCHKIN’ s3 work 
on this subject. It is of some interest that the death temperature is lowered 
by fatigue to 37° C., and by copper sulphate to 42° C. This emphasizes again 
the marked lability a certain cell-proteins, and reminds one of LEPESCHKIN’S 
results showing that they are coagulable even by pressure. 
Bose is adding much to the subject of plant response, but his excellent 
methods could add much more if they were applied in the light of our modern 
knowledge of the physics and chemistry of living cells and of plant response in 
general.— WILLIAM CROCKER. 
Biology and capillary analysis of enzymes 
Gritss! has brought together in book form the results of his work on 
enzymes, which has extended over a period of several years. Some of his con- 
3 Ber. Deutsch. Bot. Gesells. 30:703-714. 1913. 
Griss, J., Biologie und Kapillaranalyse der Enzyme. 8vo. pp. vi+227. 
col. pls. 2. figs. 58. Berlin: Gebriider Borntraeger. 1912. M. 16. 
