Physiology of the carbohydrates : their application as food and relation to diabetes / by F. W. Pavy.

Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: Physiology of the carbohydrates : their application as food and relation to diabetes / by F. W. Pavy. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    the process—that clecompositious and substitutions, for example, take place in the molecules of the green protoplasm. This possibility obtains some probability from the observation that in many (not all) cases the chlorophyll substance gradually decreases in quantity and at length disappears entirely, while the stai-ch-grains are growing in it. . . . I hold it as probable that in this process the proteid substance of the assimilating chlorophyll itself co-operates and under- goes a change. The purport of what is here said is that proteid plays a partici- pating part in the process of deposition of carbohydrate as fabric and as store material—cellulose, starch, &c. It is true, the grounds of reason- ing, as yet within our reach, do not supply the tangible evidence of the splitting off of carbohydrate from proteid matter by disruptive meta- bolism that is supplied of its entry by the exercise of constructive metabolism. Viewing all the circumstances, however, it is pardon- able to surmise that the one stands as a natural corollary to the other. Cai'bohydrate is a co-operating factor in the construction of proteid. It is deposited in a foim diifei'ent from that in which it reaches the seat of deposition—a form, even, Avhich may be said to present a semblance of organised sti-ncture, and it is undoubtedly through the agency, and only through the agency, of proteid as living protoplasm that the deposition is effected. With all this, the discovery, arrived at quite independently by analytical manipulation, of the glucoside constitution of ])roteid matter agrees, and even might natui-ally be expected to follow. It supplies just the link that is wanted to fit in with the other links and complete the chain. Under the view set forth, proteid matter, through its glucoside con- stitution, becomes of functional import in a manner, and to an extent, not hitherto definitely thought of. That its carbohydrate should be susceptible of cleaving off under exposure to certain influences (it nuiy be considered tliat ferment agency constitutes one of them) is only in accord with the condition that is known to exist in the case of other glucosides. The cellulose, starch, &c., deposited as above represented, are in a lower state of hydration than tlie sugar reaching the seat of the deposition. The position may or may not be analogous, but in any case it is an interesting circumstance that the carbohydrate derivable