Miscellaneous. 387 



and contents, the starch being deposited from without inwards > 

 These two views have been considered completely at variance with 

 each other. I trust, however, to be able to show, that while neither 

 is absolutely false, neither fully accounts for all the phsenomena 

 observed in the development of starch. With regard to the first 

 view, the balance of evidence certainly appears in favour of the exo- 

 genous, so to speak, development of starch ; that is, that the starch 

 is deposited in layers, the inner layers being formed first. As our 

 esteemed President observed at a former Pharmaceutical Meeting, 

 " If you examine the young tuber of the potato, you find only a 

 few fully-formed starch grains, and numbers of small, round, incom- 

 plete grains ; while in the mature tuber the reverse is the case — the 

 majority of the starch grains are fully formed, and only a few of the 

 small, incomplete grains are met with. If, however, the fully-formed 

 starch be carefully examined, the inner concentric layers are found to 

 be circular, and to present, in fact, precisely the figure and appear- 

 ance of the small, undeveloped grains, leading thus to the inference 

 that the remainder of the starch has been deposited round these small 

 granules." Now there is no doubt that, as far as it goes, this is a 

 true statement of fact. It appears to me, however, that it does not 

 fully explain all the phsenomena. The starch is usually free in 

 the sap, and in those instances in which it is met with adhering to 

 the cell-wall, I think it is only entangled in the mucilaginous proto- 

 plasm. Yet we cannot discover any proof, by the use of tests or 

 other means, of the existence of starch, as such, in the cell-sap. Von 

 Mohl supports this conclusion. To me it appears that starch is not 

 at all soluble in water, nor in any state of combination as starch. But 

 instead, we find gum and other matters in the cell-sap, of which 

 starch may be formed, but not starch itself. I think gum, starch 

 and sugar, members of one series, each higher in its state of organi- 

 zation than the other, the crude compounds absorbed by the fibrils 

 of the root being transformed first into gum. If we adopt Schleiden's 

 view, I do not see how we are to account for the deposit of starch. 

 If it be a mere chemical product, it seems singular that it should 

 only be deposited in such definite forms, and never on the cell-walls 

 or on the chlorophyll granules which sometimes occur in the same 

 cell with the starch. 



There is, however, the view of its composition advocated by Criiger. 

 He asserts that the primordial utricle is the source of the starch ; 

 that the starch granule first appears as a mere point, not coloured blue 

 by iodine ; and that, in all stages of the starch granule, a layer of a 

 nitrogenous substance, coloured yellowish by iodine, covers the 

 granule. This layer he looks upon as altered protoplasm, in the 

 course of transition to starch. He obtained plants in which the 

 starch grains were few in number, and in which they were imbedded 

 in the protoplasm lining the cell. I do not see, however, how this 

 view is to be applied in all cases ; in the potato, the cells are quite 

 filled with starch — all cannot be imbedded in the protoplasm ; besides, 

 protoplasm is nitrogenous, starch is not ; protoplasm, therefore, caix- 



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