206 
On the Moveable Steam-Engine. 
4thly. (We may add) From tlie evil effects of exposure to dust 
and wet. 
Mr. Wells concludes that the wear and tear of a locomotive 
must be estimated at fully 20 per cent, above that of a fixed 
engine. Considering-, however, the large items already inserted 
in these annual accounts for repairs of tubes, boilers, &c., for the 
engines, and considering, on the other hand, how improvement 
is constantly superseding older threshing-machines, it appears to 
me safe to estimate the depreciation both of engine and machine 
at 20 per cent. 
XIII. — Remarks on the Composition of the Blood, and jirincipally 
with Reference to those Diseases of, Cqttle ,<;ind Sheep in lohich 
the Fluid undergoes important Pathological Changes. By James 
Beart Simonds, Professor of Cattle Pathology at the Royal 
Veterinary College, Veterinary Inspector to the Royal Agri- 
cultural Society, &c. 
In a lecture on the structure and diseases of the organs of 
respiration and circulation, published in the Society's ' Journal,' 
Vol. X., page 570, et seq., some observations were made by me 
on the component parts of the blood, several of which it will be 
necessary to repeat here, with a few additions, for the sake of 
unity and completeness. In the present paper, however, it will 
be my aim to avoid as much as possible entering on disputed 
points of the physiology of the fluid and. of the several assigned 
causes of the changes it undergoes under ordinary circumstances 
both within and without the vessels. To attempt this would 
draw me from the practical object I have in view, and perhaps 
render the paper less attractive to the majority of the readers of 
the Journal. 
The slightest reflection on the organization of an animal body 
will suffice to show that it is composed of solid and fluid parts. 
It is not, however, so well known that the circulating fluids com- 
pose no less than a third part of the weight of the individual 
animal, and that all the so-called solid parts of the frame were at 
one time in a state of fluidity. The fluids met with are various, 
consisting chiefly of the blood, the lymph, the chyle, and 
other secretions. The latter named, as well as the lymph, 
depend immediately on the blood itself for their existence, while 
this, in its turn, has its chief source in the chyle — the fluid which 
is produced in the animal organism by the processes of digestion 
and assimilation of the food on which the creature subsists. The 
several changes which the food undergoes before it becomes con- 
