3 
ae a 
: 
1894. ] Anatomical and Physiological Researches. 295 
ous increase of the sensitiveness to the stimulus; if it con- 
tinues to increase, an inhibition of the growth in length must 
result. 
VIII. The retardation is not produced by a depression of 
the hydrostatic pressure. The comparison of the turgor of 
cells from plants provided with weights and plants without 
weights showed a higher pressure in the plants subjected to 
traction. A similar retardation and increase in turgor was 
produced by gypsum jackets. In roots, especially, the pres- 
sure reached a considerable height and is perhaps of consid- 
erable biological importance. The investigations of Eschen- 
hagen, Wortmann, and Zacharias are also analogous and 
showed with increase in turgidity, a retardation or inhibition 
similar to that produced by traction.—F. D. HEALD, Umz- 
versity of Wisconsin. 
