Volume 1

A text-book of human physiology : including histology and microscopical anatomy with special reference to the requirements of practical medicine / by L. Landois ; translated from the seventh German edition with additions by William Stirling.

Landois, L. (Leonard), 1837-1902. Lehrbuch der Physiologie des Menschen. English

Date:: 1891

Credit: A text-book of human physiology : including histology and microscopical anatomy with special reference to the requirements of practical medicine / by L. Landois ; translated from the seventh German edition with additions by William Stirling. Source: Wellcome Collection.

46/602 (page 6)

$Fig. 5. Drop of human blood showing some of the red corpuscles in rouleaux. of the microscope. The lens is then focussed for the squares. In a few minutes the corpuscles havrsuTk to tlfe bottom of the cell, and are seen at rest on the squares. _ The number in ten squares^?then ^^^^^^ and this, multiplied by 10,000, gives the number m a cubic millimetre ^Toestimate the colourless corpuscles only, mix the blood with 10 parts of O'ö per cent, solution of acetic acid, which destroys all the red corpuscles {Ihoma). 3 HISTOLOGY OF THE HUMAN RED BLOOD-COKPUSCLES AND THE EFFECT OF REAGENTS.—When observed singly, human red blood-corpuscles are bi-concave circular discs of a yellow colour with a slight tinge of green; they seem to be devoid of an envelope, are cer- tainly non-nucleated, and appear to,be homo- geneous throughout (fig. 5;. Each corpuscle consists (1) of a framework, an exceedingly pale, transparent, soft protoplasm — the stroma; and (2) of the pigment or haemo- globin, which impregnates the stroma,^ much as fluid passes into and is retained in the interstices of a bath-sponge. (A) Effects of reagents on their Vital Phenomena.—The blood-corpuscles present in shed blood— or even in defibrinated blood, when it is reintroduced into the circulation- retain their vitality and functions undimin- ished. Heat acts powerfully on their vitality, for if blood be heated to 52° C, the vitality of tl^e j-ecL corpuscles is destroyed. Mammalian blood may be kept for four or five days in a vessel under iced water, and still retain its functions; but if it be kept longer, and reintroduced into the circulation the corpuscles rapidly break up—a proof that they have lost their vitality. The red corpuscles in freshly shed blood sometimes ex- hibit a pecuHar mulberry-like appearance (figs. 6, 7, g, li). [This is called crenation of the coloured corpuscles. It occurs m cases ot poisoning with Calabar bean; and also by the addition of a 2 Yw 6 per cent, solution of common salt.] The blood of many persons Crenation of human crenates spontaneously-a condition ascribed to an active contrac- red blood - cor- tion of the stroma, but it is doubtful if this is the cause, ihe lecl puscles. X 300. corpuscles of the embryo-chick undergo active contraction. (B) On their External Characters.—(a) The colour is changed by many gases. 0 makes blood scarlet, want of 0 renders it dark bluish-red, CO makes it cherry- red NO violet-red. There is no difference between the shape of the corpuscles in arterial and venous blood. All reagents {e.g., a concentrated solution of sodic sulphate), which cause great shrinking of the coloured corpuscles, produce a very bright scarlet or brick-red colour. The red colour so produced is quite different from the scarlet-red of arterial blood. Reagents Avhich render blood-corpuscles globular darken the blood, e.g., water. [The contrast is very striking, if we compare blood to which a 10 salt has been added with blood to which water has been added With reflected light the one is bright red, and the other a very dark deep crimson, almost black. J {h) Formation of Rouleaux.—A very common phenomenon in shed blood is the tendency of the corpuscles to run into rouleaux (figs. 1, A3; 5). Conditions that increase the coagulability of the blood favour this P?^^^°«;™';f ^f^.,;^ ascribed by Dogiel to the attraction of the discs and the formation of a sticky s^^bstance [Tlie cause of the formation of rouleaux is by no means clear. The corpuscles may be ^e acl^^ed f om each other by gently touching the cover-glass, but the rouleaux may re-form. Listei suggested$