328 
Physiologie. 
depuis la reconstitution des vignobles franqais sur vignes ameri- 
caines. Daniel, dans un jardin situe ä Erquy, au bord de la mer, 
a taille des vignes de chasselas, en totalite ou en partie, les unes 
au moment de la floraison, les autres apres que le grain bien noue 
avait la grosseur d’un grain de plomb. Dans le premier cas la cou- 
lure (absence de fermentation) a ete plus considerable dans les 
pieds tailles que dans les pieds normaux; il n’y a pas eu accentua- 
tion du millerandage. Dans le deuxieme cas, le millerandage a et£ 
plus energique dans tous les pieds tailles. Les vignes incompletement 
taillees portaient sur les rameaux tailles a peu pres le meme nombre 
de grains normaux et de grains millerandes; sur les rameaux non 
tailles les grains normaux predominaient. On peut conclure que le 
millerandage est fonction des conditions d’alimentation de la grappe, 
Daniel l’explique par une plethore aqueuse. Jean Friedei. 
Dunstan, W. and T. A. Henry. The Chemical aspects of 
Cyanogenesis. (Report British Association for the Advancement 
of Science, York, 1906. p. 145—157. 1907.) 
This paper contains a valuable summary of the authors’ work 
on Cyanogenesis, an account of recent work upon the physiological 
significance of the process and a .summary of current hypotheses as 
to the possible Chemical mechanism of proteid synthesis through the 
stage of prussic acid. 
The Constitution and hydrolysis of the several well established 
cyanogenetic glucosides are expounded. In amygdalin, sambunigrin, 
prulaurasin and dhurrin the cyanohydrin group is associated with 
the non-sugar radicle and of these four, the second and third are 
probably isomeric with Fischer’s mandelic nitrile glucoside. Further 
investigation of their sugar radicles should settle this point. 
In lotusin the cyanohydrin group is associated with a maitose 
radicle. 
Phaseolunatin is the best known natural type of glucoside con- 
taining no cyclic radicle, it is an « dextrose ether of acetonecyan- 
hydrin. 
The evidence for the individuality of the enzymes associated 
in nature with these different glucosides is discussed. The fact that 
emulsin attacks all these except lotusin indicates, from Fischer’s 
work, that all except this must contain ß glucose radicles. 
As regards the physiological significance of HCN there has been 
coming on a change of opinion from regarding it as a waste product 
or possibly protective towards the view that it is an important Up¬ 
grade stage in proteid synthesis. This change was initiated by 
Treub’s work on Pangium. Recent observers have shown that with 
various plants there may be a great increase in the amount of 
HCN during the seedling stages; thus even the sweet almond may 
come to contain *04°/ 0 . In many cases nitrogenous manuring increases 
the amount present. 
The various theories of the formation of HCN in the plant are 
discussed from a Chemical point of view. The Mey er-Schulze-Bach 
view, according to which nitric acid is reduced by formaldehyde to 
hydroxylamine and so through formaldoxime to hydrocyanic acid by 
dehydration, is contrasted with Gautier’s theory that HCN is 
formed, with C0 2 and H 2 0, by the direct interaction of nitric acid 
and formaldehyde. It is suggested that the greater amount of HCN 
observed in dry seasons or in individuals grown in dry habitats 
