On the Influence of Sudden Changes of 
Turgor and of Temperature on Growth. 
BY 
RODNEY H. TRUE, B.S., M.S. 
A LTHOUGH growth, as influenced by external conditions, 
has received much attention from plant-physiologists, 
a detailed study of the effects called forth by sudden change 
in these conditions has not yet been made. 
The object of the investigation yielding the results given 
in the following pages was to ascertain more accurately the 
effects on growth brought about by sudden changes of turgor 
and of temperature. For the sake of convenience, the sub- 
jects will be treated separately. 
I. The Effect of Sudden Turgor Changes. 
Historical. 
Cohn 1 seems to have first called attention to the effect of 
sudden changes of the concentration of the substratum upon 
organisms living in it. He found that either too rapid an 
increase or decrease of the concentration of the medium 
injured or killed Infusoria present, and he regarded the 
source of the injury to be the endosmotic processes taking 
place in the bodies of the animals. 
Strasburger 2 noted a very similar action in the case of 
swarm-spores. 
1 F. Cohn, Entwickelungsgeschichte der microscopischen Algen und Pilze. 
Nova Acta Akad. Caes. Leopold. Bd. XXIV (1854), Th. i, p. 132. 
2 E. Strasburger, Wirkung des Lichtes und der Warme auf Schwarmsporen. 
Jenaische Zeitschrift fur Naturwissenschaften, Bd. XII (1878), p. 66. 
[Annals of Botany, Vol. IX. No. XXXV. September, 1895. 
D d 
