AGRICULTUKAL BOTANY. 427 



else that the effects of the friction of the starch grains or the impetus of their 

 descent are commuuicatecl to the medium. It is suggested that a way is thus 

 opened for further study of the proi>erties of the several cell contents. 



The carbohydrates of the snowdrop leaf and their bearing on the first 

 sugar of photosynthesis, J. Parkin (Bio-Chcm. Jour.. 6 {1911), yo. 1, pp. l-Jjl, 

 fig. 1). — This is a fuller account of work already in part reported (E. S. R., 21, 

 p. 319). 



The results as first given have been confirmed. Only 3 carbohydrates were 

 present in these leaves in appi'eciable quantity, viz, sucrose, glucose, and fruc- 

 tose. The total quantity of these in a leaf was from 20 to 30 per cent of the 

 dry substance, or from 4 to 6 per cent of the fresh, active leaf. The greater pro- 

 portion in the lower part of the leaf may be due to the greater shading of this 

 part as the amount was greater in leaves from thick clumps. The lower part of 

 the leaf seems to function somewhat as storage tissue for sugars when obscured. 

 It seems that, as spring advances, the hexoses increase at the expense of the 

 sucrose. The leaves, when detached and insolated, contain decidedly more su- 

 crose than their controls, while the quantity of hexoses remains much the same. 

 The fructose as a rule is in excess of the glucose. Leaves when darkened lose 

 sucrose rapidly during the first 48 hours, after which the proportion remains 

 fairly constant. 



In general, the results favor the conclusion announced by Brown and Morris 

 that sucrose is the first sugar to arise on photosynthesis, and that the two 

 hexoses, glucose and fructose, as well as starch, are derived from sucrose. 

 Important services by sucrose in relation to circulation, storage, and trans- 

 formation purposes are suggested. 



The origin and function of pentosans in plants, C. Ravenna, O. Cebeseb, 

 and O. MoNTANARi {Gaz. Chim. Ital., 1,1 {1911), II, No. 2, pp. 115-129).— Suh- 

 stantially the same work as previously reported (E. S. R., 24, p. 228), with the 

 conclusions that the pentosans probably have their origin in sugars and that 

 among other functions they perform that of storage of reserve materials. 



The significance of mucilage in the germination of seeds, C. Ravenna and 

 M. Zamokani {Gaz. Chim. Ital, 41 {1911), II, No. 2, pp. 1S8-U3).— This is sub- 

 stantially the same as a report previously noted (E. S. R., 24, p. 534). 



Dimorphism of chlorophyll grains in some plants, U. Giovannozzi {Nuovo 

 Gior. Bot. Ital, n. ser., 19 {1912), No. 1, pp. 39-51, figs. 2).— Studies carried on 

 with numerous plants, more particularly Portidaca oleracca and AJtcnianthera 

 sessilis amwua, led the investigator to the conclusion that the dimorphism of 

 chloroplasts, observed in numerous and widely separated groups, is related to 

 the environment of the plant and the principal function of the cells under 

 observation. In leaf parenchyma of mainly assimilative function the chloro- 

 plasts were found to be larger and more active, while in regions more con- 

 cerned with conduction these grains were reduced in size and seemed to be 

 less active. Heat, dryness, and light also appear to show some relation to the 

 differences observed. 



Remarks on a new method of studying stomatal aperture of stomata, 

 Emmy Stein {Ber. Dent. Bot. Gesell, 30 {1912), No. 2, pp. 66-6S ) .—Concerning 

 the method described by Molisch (E. S. R., 27, p. 221) which is stated to have 

 been previously discovered and used by others, the author makes the following 

 claims : 



The number of substances suitable for the puriwses of infiltration is much 

 larger and the range of possibilities of the method is much greater than claimed 

 by Molisch. For example, melted paraffin, entering only wide apertures, and 

 petroleum ether, which penetrates exceedingly minute ones, are much further 

 apart than are alcohol and benzol. It is claimed that estimates of apertures 



