MEMORANDA. 163 



tlio same time it would afford an argument for those wlio douLt tlie dis- 

 tinct existence of a determinate layer or primordial utricle on the outside 

 of the prolo})lasm. Our author's statements as to the pdlicular character 

 of the apparent membrane described hy Kiigeli on starcli and Chlorophyll- 

 corpuscles, would seem to ap])ly to some extent to the so-called pri- 

 mordial utricle. Pringsheim has recently published some important ob- 

 servations oil this head, which I trust to be able shortly to test and 

 report on. 



" 'J'he observations of Mr. Grundy agree, in some respects, with tiiose 1 

 have made in a great variety of cases, but the stria} are certainly not 

 superficial, and I doubt the existence of the outer membrane. 1 think 

 there is merely' a pellidt of protoplasm, coagulated on the starch-grain 

 when re-agents are added. This would appear to dip between the con- 

 stituent grains of grouj^s ; in some cases, however, the interposed pellicle 

 becomes obliterated, and the groups, \nos,t\y pairs in such cases, have the 

 outer layers common over the whole. It seems to me that there is a 

 fallacy in the various accounts of the membrane of the starch-granule, 

 foimded on the experiment of boiling starch, assuming, as I do after 

 lepeated experiments, that tlie main body of the structure is that of con- 

 centric lamin<'e of a tough material. If there were an enclosing membrane 

 distinct from the starch-layers, thick enough to bear expanding to many 

 hundred times its original su]ierficial dimensions, this must be thick enough 

 wjien vmex]ianded to be clearly visible as a well-defined coat. The saccate 

 bodies obtained by boiling really result from the whole softened substance 

 of the granules beconn'ng blown out (like india-rubber bottles) by a j^ro- 

 cess of endosmosis. T'he internal subsiarice softens and absorbs water 

 niore readily than the other— a sufficient cause for the endosmosis. Iliis 

 difference of condition of the layers is pro^-ed by an experiment 1 have 

 repeateilly made with fresh ])Otato-starch. If we attempt to cut it with 

 a knife, it breaks with a roughish fracture, like a lump of partially-hardened 

 clay ; if the fragments are placed in cvhl water, the internal jiart of the 

 starch will often swfU and protruuc irregularly, while the outer layers 

 retain their shape. I cannot confirm Mr. Grundy's statement, that the 

 " skins " can be boiled until they no longer take the blue (or bluish) 

 colour with starch. Still, since after boiling, as in treatment with sul- 

 phuric acid, the colour of the substance with iodine tends more and more 

 to pinkish purple, it is possible that long boiling may change this condi- 

 tion, just as roasting does." 



On the Microscopical SlrucJiirc «f She TIctoria IScgia (l,iiudl.) — 



The stomata are nearly circular, fonned of two crescentic 

 cells. They are minute, measuring- only the l-960th of an 

 inch in diameter, and so closely placed that one square inch 

 of epidermis will contain 139,848. An ordinary- sized leaf, 

 4 feet in diameter, with a surface of 1850 08 square inches, 

 will thus contain upwards of twenty-five millions of stomata 

 (25,720,937). 



The lower surface of the Victoria leaf is somewhat peculiar. 

 It exhibits no stomata, but is thickly clothed with flexuous 

 hairs, consisting of cylindrical cells, and arising each from a 

 small round basal cell very distinct both from the other cells 

 of the hair and those of the epidermis, which latter are filled 

 with diffused colouring matter, mostly red, but in some blue, 



M 2 



