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

  • Pavy, F. W. (Frederick William), 1829-1911.
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: The 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 Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    fermentability, cjumnt he poiisideved to iiivalidiitp the positive evidence that is adducible. Optical activity is a property in ronnoxioii with which ranch divei'sity exists, some sugars being dextro-rotatory, others laevo- I'otatory, others inactive, from the neutralising effect of the pi'esetice of varieties with opposite rotatory powers, and, again, others abso- lutely inactive, and not to be resolved into component active sngars. Further, a sugar with rotatory power in one direction is susceptible of being converted into a sugar with a rotatory power in the opposite direction, as is exemplified by the convertibility of dextrose into ]a3vulose (Fischer). Fermentability is a property similai'ly circumstanced with regard to diversity. Sugars, it is known, exist, even amongst the glucoses, which are not fermentable, and it may happen that one form of a particular group having one kind of optical activity is fermentable, whilst another form, with an opposite kind of optical activity, is not. For instance, ordinary l^vulose, which is Ifevo-rotatory, fer- ments, whilst a dextro-rotatory form of Irevnlose which has been artificially obtained is not fermentable. A similar difference is observable in the dextrose group, the ordinaiy or dextro-rotatory form of dextrose being fermentable, whilst the Itevo-rotatory form is not (Fischer). Whatever may subsequently prove to be attainable, it is not contended that the sugar from proteid matter has yet been brought into the form of glucose—indeed, the evidence is to the effect that it has not. Tf, therefore, so resistant to passage into glucose, there is nothing surprising- in its being resistant to the fer- menting influence of yeast. Whilst the recognition of the glucoside constitution of pi'oteid matter was entirely founded upon the information drawn from its subjection to disintegration, the information derivable from the opposite consideration fits in and supplies confirmatoiy testimony. It will, in what immediately follows, be shown, upon irrefutable grounds, that in the construction of proteid matter by the synthetic power of protoplasmic chemistry, carbohydrate matter is a partici- pating agent. If carbohydrate matter thus enters into the construc- tion of the proteid molecule, it only stands in harmony with what might be expected, that it should be susceptible of being again liberated with tlie occurrence of disintegration.