358 BOTANICAL GAZETTE Iapril 



cooling 2-3 cm. zones of petioles and stems to a temperature of 2 . 5-3 C. In 

 Bryophyllam, when such zones of the petiole are cooled, the broken correlation 

 is manifested by development, not only in the notches of the leaf treated, but 

 by development in the notches of the opposite leaf, as well as leaves both up 

 and down the stem. The effect extends farther in the basal direction than in 

 the apical. This indicates marked complexity in the correlation inhibitive 

 effects. In Phaseolus the axial buds below the cooled zone grew. In Saxifraga 

 sarmentosa the runner tip could be thus isolated. All of these results favor 

 McCallum's view that correlative effects are brought about by conduction of 

 stimuli, mainly inhibitory stimuli, and not by movements of materials. 



Wm. Crocker. 



* 



Fermentation, — Euler and Svanberg 17 made a study of alcoholic fer- 

 mentation in an alkaline medium in which P = 8. Top yeast and Torula gave 

 about equal weights of carbon dioxide and alcohol, each equal to 30-336, of 

 the weight of the sugar fermented. Glucose, fructose, and invert sugar were 

 fermented with about equal speed, mannose about 30 per cent as fast, and 

 galactose very slowly. Invertase is active in this medium and maltase inactive. 

 The following are the maximum alkalinities in which cell division occurs in 

 the various yeasts: Frohberg Unterhefe B., P H = 7.7-8; Brennerei Oberhefe 

 S.B. II, P H = 7.3-8.4; Sacch. ellipsoideus, P H = 7.9; Pseudosacch. apicidatus, 

 P H = 7 • 6. Increase in weight occurred in S.B. up to P H = 8 . 5. For Frohberg 

 Unterhefe H the full curve of acid sensitivity was worked out and the 

 optimum was found to be at Ph = 5. — Wm. Crocker. 



Exudation of water by leaves. — Miss Flood 18 has recently investigated 

 the exudation of extremely pure water by the leaf tips of Colocasia antiquorum. 

 Examination of sections of leaf tips showed no membrane, or other structure 

 which might act as a filter, between the vascular system of the leaf blade and 

 the pores leading to the tip. Solutions of India ink, gelatine, and starch 

 were forced through the vascular system and exuded at the tips. Exudation 

 from leaves attached to the plant continued at the normal rate when leaf tips 

 were anaesthetized. Miss Flood is of the opinion that cells lower down in 

 the plant are responsible for the secretion and filtration of water, but finds no 

 evidence for the existence of such cells except in the root. — J. M. Arthur. 



Colorado grasslands. — Reviewing the investigations of the grasslands of 

 Colorado by himself and others, Ramaley** enumerates all the association 



v Euler, H., and Svanberg, O., Enzymatische Studien uber Zuckerspaltungen 



Hoppe-Seyler Zeit. Physiol. Chem. 105:187-239. 1919. 



Margaret 



Proc 



Roy. Dublin Soc. (N.S.) 15: ph. 2. 1919. 



Ram 



Bull. Torr. Bot. Club 46:37-52. figs. 2. 1919. 



