Page:Proceedings of the Royal Society of London Vol 60.djvu/370

Rh It gives negative results with the reactions of Liebermann and Adamkiewicz, but gives the typical red coloration when the solid plates are heated with an alcoholic solution of alloxan (Krasser’s reaction). It is separated from solution by neutral salts in a manner similar to the colloid a and Grimaux’s colloids. The scum also redissolves in distilled water giving an opalescent strawcoloured solution. It is precipitated by silver nitrate, lead acetate, and mercuric chloride, as well as by phosphotungstic, phosphomolybdic, and trichloracetic acids, and by acetic acid and potassium ferrocyanide.

In the entire absence of salts it is not coagulated on boiling, but, on the addition of a trace of a soluble salt of either sodium, magnesium, barium, strontium, or calcium, a coagulum is obtained on heating to 74° C.

The fractional heat coagulation of this substance will be dealt with in a subsequent section.

The effect produced by the intravascular injection of various quantities of this body is illustrated by the following experiment:—

Experiment 8.—Brown mongrel (weight 27 lbs. 7 oz.) ; anaesthetised with ether and morphia. The jugular vein on the one side, and the carotid artery on the other, were exposed, and cannula^ inserted into them. The colloid (3 was injected into the jugular vein, and samples of blood withdrawn from the artery. The following table shows the rate of clotting of the various samples :—

(1) Before injection of the colloid, the blood clotted in 10 minutes 30 seconds. (2) 5 c.c. of 0‘75 per cent, solution of colloid dissolved in 0'75 per cent, saline injected. A firm clot formed in 17 minutes 8 seconds. (3) 10 c.c. more injected. Loose clot in 22 minutes. (4) 10 c.c. more injected. Firm clot in 31 minutes. (5) 10 c.c. more injected. Firm clot in 13 minutes. (Q) After interval of 5 minutes a second sample of carotid! blood formed a firm clot in 7 minutes 30 seconds. (7) 7 c.c. more injected. Firm clot in 7 minutes 30 seconds.. (8) 10 c.c. more injected. Firm clot in 6 minutes. (9) 15 c.c. more injected. Firm clot in 3 minutes. (10) 10 c.c. more injected and proved fatal.

Immediate post-mortem examination revealed loose clots in vena' cava inferior, and jugular vein, and pronounced clots in portal vein, and right ventricle. This experiment shows the “ negative ” after injection small quantities of the colloid f3, and the typical hastening of the coagulability of the blood withdrawn from the carotid after the intravenous injection of