1900] CURRENT LITERATURE 717 
depends upon the correlation between the pressure of epidermal and guard 
cells. The phenomenon he considers as one of irritability, the same as nycti- 
tropic or other irritable movements. An excellent bibliography is appended. 
— W. B. McCALLuM. 
PROFESSOR PFEFFER, in a lecture upon reproduction and the signifi- 
cance of amitosis,’ calls attention to the fact that the comparative rarity 
of the amitotic division of the nucleus, together with the enormous attention 
paid to karyokinetic figures, has led to the belief that cells which show ami- 
tosis have lost their reproductive power, and that direct nuclear division 
presages the death of the cell, a view which is upheld by Strasburger, Ziegler, 
von Rath, and many other prominent animal and plant cytologists. That 
this view is erroneous is proved by the behavior of Spirogyra under certain 
conditions of culture. The cells of this plant continued to grow and divide 
amitotically for periods of twelve hours or more, the protoplasmic structures 
produced being in all respects similar to those coming from mitotic divisions, 
and when the plants were removed to a normal medium the customary 
methods of cell-multiplication were resumed without variation. The same 
treatment induced amitotic division in Closterium, and also in the stamen 
hairs of Tradescantia, but failed to do so in Phaseolus and Lupinu 
Mitosis and amitosis were observed in neighboring cells in cae forma- 
tions, and the total results from all the material examined show that amitosis 
may occur in young rapidly growing embryonic tissue as well as in older 
cells. The occurrence of either method of nuclear division is under control of 
the regulatory mechanism of the cell. Both are performed as specific reac- 
tions to environmental conditions, and intermediate stages of division may 
be sought for during the alteration of these external conditions. It is not 
improbable that even such highly specialized structures as egg cells may 
divide at certain times by amitosis. 
It follows that the nuclear figures are not vehicles of heredity in the 
Sense in which they have been so widely considered, a conclusion which has 
already forced itself upon the workers who have gone most deeply into the 
subject. Not only must less hereditary value be conceded to the chromo- 
somes, but it must be admitted that the nucleus is not the sole bearer of the 
qualities of the organism or cell.—D. T. MAcDouGAL. 
BOTANISTS probably do not fully appreciate the value of the Experiment 
Station Record, issued by the Department of Agriculture, as an index to cur- 
rent literature. In the tenth volume, just completed, over 2000 articles have 
been abstracted, of which more than 1200 were foreign. Of these abstracts 
127 are classified under botany; 27 under fermentation and bacteriology; 34 
™ Abhandl. d. Math.- -Phys. Classe d. Konigl. Sachs. Ges. d. Wiss. zu Leipzig. 
Sitzung von 3 Juli, 1899. 
