Page:Manual of pathological anatomy (IA manualofpatholog00jone).pdf/46

30 WATER. diminished, This, however, seems very questionable with regard to sodium chloride.

WATER.

Lecanu’s estimate of the mean quantity of water in 1,000 parts of blood is 790; he found more water in the blood of women than in that of men, more in the blood of children and of aged and debilitated persons than in that of vigorous adults, more in the lymphatic than in the sanguineous temperament. It is clear that the whole quantity of water is not contained in the serum, a certain proportion, which must vary with the specific gravity of the blood, is enclosed in the red corpuscles, and holds their colouring matter in solution. The scrum of arterial blood and of portal vein blood is said by Lehmann to contain more water than that of venous blood gencrally. It is a very remarkable cireum- stance, and strongly indicative of wise provision, that it is very difficult to demonstrate by analysis an actual inerease of the quantity of water in the blood after copious drinks have been taken, Denis and Schultz are at issue as to whether such an increase is detectible or not. This seems to show how exactly the vascular system is kept at a certain degree of tension, so that in proportion as absorption at one part takes placc, excretion at another ensues correspondingly. The effect of bleeding and starving, which was before noticed, of reducing tho amount of globules, tells, of course, proportionally, in increasing the quan- tity of water; this can easily be ascertained, as it is in great measure relative; the merely positive increase is much more doubtful. Andral mentions a case of confirmed chlorosis, in which the water in the blood amounted to 867:9, an increase of nearly 78 parts per 1000. Lchmann states that in the beginning of most diseases, especially acute ones, the blood is found more watery than natural, the serum, however, at the same time, being richer in solid contents. He accounts for this by supposing that the material which should haye been applied to the formation of the globules, or which results from their decay, remains in the serum. During the first ten days of typhus, the first stage of scarlet foyer, measles, and cholera, this increase in the watery constituents of the blood does not appear to take place,

In cholera the most striking diminution in the proportion of water takes place; apparently as a consequence of the immense transudation of fluid into the intestines. Other changes are, how- ever, also present; the scrum becomes not only richer in albu~ men and salts, but also appears to withdraw from the corpuscles the salts proper to them, viz., potassium salts and phosphates (Kiihne). There are also physiological variations in the per- eentage of water, which diminishes at first in steryation, but recovers itself if abundant water be ingested. Tho amount is also diminished by taking much salt, �