DR DAVY'S MISCELLANEOUS OBSERVATIONS ON THE BLOOD. 29 



so ; now, when the bottle was turned on its side, it ceased to flow. On the fol- 

 lowing day it was so firm that it bore inversion without flowing ; no serum had 

 separated. Examined on the 13th of December, the only change perceptible was 

 that it was rather firmer. On the 1st of January it was more carefully examined. 

 On withdrawing the stopper, as might have been expected, the smell of the 

 ammonia was very powerful, indeed unendurable. The coagulum was found 

 of the consistence of a pretty firm jelly, readily yielding to pressure, but not 

 adhering to the glass rod impressing it. The whole mass was easily removed, 

 retaining its form unbroken ; and such was the adhesiveness of its substance — 

 i.e., of its particles to one another — that the mass admitted of being divided with 

 a scissors without its soiling the instrument. A portion of it put into water did 

 not immediately colour the water ; from black it became dull brown. Examined 

 with the microscope under compression, it exhibited a finely granular surface, 

 through which were scattered globules of a less diameter than the blood corpuscles 

 — these, it may be inferred, contracted. 



In other experiments, made within a few days of each other, with smaller 

 proportions of the volatile alkali, the effect has been found to vary. 



When 12 grs. of aqua ammonite, of the same strength as that last mentioned, 

 were mixed with 465 grs. of the blood of a turkey, the instant it was shed, the 

 coagulation was retarded about 20 minutes. On withdrawing the stopper the 

 following morning there was a strong smell of ammonia ; the crassamentum was 

 found of tolerable consistence, and was surrounded and covered with red serum, 

 which owed its colour chiefly to red corpuscles suspended in it of a globular form, 

 a change from their normal form evidently owing to the action of the alkali. 

 Examined again after twenty days the coagulum was found firmer ; it admitted 

 of being taken out as an entire mass. 



In a third experiment 2 - 5 grs. of aqua ammonise were mixed, as in the former 

 instances, with 572 grs. of the blood of a fowl. After two hours the blood was found 

 feebly coagulated and viscid, in a semifluid state, sluggishly flowing like tar. 

 When a portion of it was poured into water, it did not mix with the water, but 

 kept entire, retaining its viscidity. What remained, examined the following 

 morning, was found divided into a somewhat denser crassamentum, still semi- 

 fluid and viscid, and a red somewhat viscid serum, abounding in red corpuscles, 

 more or less altered in form, many of them .diminished in volume, and almost all 

 of them rounded. Both the soft coagulum and the serum smelt of ammonia. 



A fourth experiment was made on the blood of a sheep, after the same manner 

 as the preceding. The quantity of the aqua ammoniae was 1 gr., of the blood 587 

 grs. Examined after about half-an-hour, the blood, still warm, was found pretty 

 firmly coagulated, and already some serum had separated. The glass stopper was 

 withdrawn, and instantly after a plate of glass, moistened with dilute hydro- 

 chloric acid, was placed over the mouth of the bottle, and left for two minutes. 



