VARIOUS BREEDS OF SHEEP IN GREAT BRITAIN. 105 
have a further illustration of the analogy that appears to 
exist, in the nature of the metamorphosis of sugar as a phy- 
siological process, and that which takes place chemically 
under the influence of an azotized compound, whose elemen- 
tary particles are in a state of molecular transition. During 
life, the higher organic constituents of the blood are capable 
of undergoing the changes of assimilation on exposure to 
contact with oxygen, and there is a considerable destruction 
of sugar effected ; for a short period after death these azotized 
constituents remain stationary and uninfluenced by oxygen, 
and with this, there is a corresponding suspension of the 
transformation of sugar; but, finally, the animal matter of 
the blood on contact with oxygen, especially during a warm 
temperature, assumes a state of decomposition, the molecular 
changes of which again excite the destruction or metamor- 
phosis of saccharine matter. 
The sugar disappears far less rapidly from diabetic blood 
under the influence of exposure to the atmosphere, than from 
healthy right-ventricular blood. From these, and a few other 
observations which he has yet been able to make on the 
blood in diabetes mellitus, the author, were he to hazard an 
opinion on the nature of that obscure disease, would be dis- 
posed to say that there appears to be a modification of sugar 
produced by the liver, which is not susceptible of undergoing 
the normal process of destruction in the animal system, and 
which, therefore, accumulating in the blood, is eliminated by 
the kidneys. The experiments of Bernard have shown that 
vegetable glucose (grape-sugar) is not susceptible of destruc- 
tion in the processes of animal life, unless converted into 
animal glucose by the agency of the liver. Diabetic sugar 
would therefore seem to bear resemblance in its physiological 
relations to vegetable, rather than to animal glucose. — Pro- 
ceedings of the Royal Society , vol. vii, No. 13. 
ON THE VARIOUS BREEDS OE SHEEP IN GREAT BRITAIN, 
ESPECIALLY WITH REEERENCE TO THE CHARACTER 
AND YALUE OE THEIR WOOL. 
By John Wilson, Professor of Agriculture in t.he 
University of Edinburgh. 
( Continued from vol. xxviii, p. 705.) 
Ryeland. — This is one of our oldest breeds, having existed 
in Herefordshire from time immemorial. Its name is derived 
14 
XXIX. 
