774 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The so-called "gluten-layer" beneath the pericarp contains neither 

 gluten nor any ferment, but small grains of a nitrogenous substance 

 imbedded in fatty protoplasm, as well as diastase. 



Formation of Calcium oxalate in Plants.*— Dr. C. Acqua discusses 

 the mode and place of formation of the crystals of calcium oxalata in 

 plants. He decides against the hypothesis that it may be formed in 

 all the turgid cells of the parenchyme, from whence it is carried in the 

 cell-sap to those where it is ultimately deposited in the crystalline form. 

 He believes, on the contrary, that the calcium oxalate, though not the 

 oxalic acid, is formed in the crystalliferous cells. The acid may be 

 formed in all the turgid cells of the cortical and medullary parenchyme, 

 where it combines with potassium, and circulates chiefly through the 

 intercellular spaces. It is there prevented from combining with the 

 calcium-salts in the cell-sap by the coating of ectoplasm ; while the cell- 

 walls of the crystalliferous cells possess the property of accumulating in 

 them calcium-salts, which then decompose the potassium oxalate, and 

 cause the deposition of crystals of calcium oxalate. This hypothesis is 

 confirmed esi)ecially by observations on Mesemhryanthemum acinaciforme 

 and Euonymus japonicus. 



Prof. A. Poli t replies to strictures made by Dr. Acqua on his previous 

 writings on this subject. 



Calcium oxalate in Plants 4 — In opposition to the statement of 

 Schimper, Dr. C. Wehmer finds that in SympJioricarpus, Alnus, and 

 Crataegus, there is no transference of the calcium oxalate from the leaves 

 to the leaf-stalk, branch, or stem, nor from the mesophyll to the vascular 

 bundles ; but that, on the other hand, the oldest leaves always contain the 

 largest amount of this salt. 



In Cratsegus the buds are found to be filled with calcium oxalate in 

 the autumn ; and this is not deposited with the first growth in spring ; but 

 only at a later period of the formation of the new organs. 



The absence of calcium oxalate in certain parasites (Bafflesia, Lathrsea, 

 Cuscuta, Cassytha) he attributes to the suppression of the production of 

 plastic substances from distant organs. 



In reply. Dr. P. G. Kohl § points out that the explanation is hardly- 

 satisfactory, since we have to do with the absence, not of oxalic acid, but 

 only of calcium oxalate; and that Lathrsea squamaria does at certain 

 times contain large quantities of starch. He also dissents from 

 Wehraer's conclusions as to the distribution of calcium oxalate in 

 SympJioricarpus, &c. 



Perfume of the Ilose.|| — M. E. Blondel states that the odour of 

 the rose is found to be principally developed in the group Centifolia, 

 and particularly in B. centifolia. The Canina group possesses an 

 analogous odour, which is, however, generally much more feeble. 

 The hybrids produced by crossing Tea Koses {B. fragrans) and Ben- 

 galese Eoses {B. semperflorens) with B. centifolia give a great 

 variety of odours; while the Noisette Eoses (hybrids of B. moschaia 



* Malpighia, iii. (1889) pp. 17-4-3, 160-6 (1 pi. and 1 fig.)- Cf. this Journal, an^e, 

 p. G55. t T. c, pp. 173-5. 



% Bot. Zt?., xlvii. (1889) pp. 141-55,169-78; Bot. Centralbl., xxxviii. (1889) 

 pp. 648-9 ; and Ber. Deutsch. Bot. Gesell., vii. (1889) pp. '216-33 (1 pi.). 



§ Bot. Centralbl, xxxviii. (1889) pp. 649-52. 



\\ Bull. Soc. Bot. France, xxxvi. (1889) pp. 107-13. 



