22 DR DAVY'S MISCELLANEOUS OBSERVATIONS ON THE BLOOD. 



With hydrate of lime, both yielded a strong ammoniacal odour. The blood cor- 

 puscles, as seen under the microscope, were found to have become rounded and 

 globular. The fibrin seemed to be permanently dyed red ; it retained this colour 

 after having been well washed, and after maceration in water for many hours. 

 Its structure was finely granular ; it showed no appearance of fibres under gentle 

 pressure, and viewed with a high power. 



The experiment was repeated, using the blood of a turkey and also of a 

 bullock. The results were similar. That on the blood of the turkey was of the 

 same duration as the preceding. That on the bullock's blood was begun on the 

 14th of December, and ended on the 7th of January. In the latter instance, 

 though no gas was evolved, the putrid blood, when subjected to the air-pump, 

 entered into violent ebullition from the copious disengagement of air, and this 

 even before the vacuum was nearly complete. It may also be mentioned, that a 

 silver probe plunged into the clot became, after a few minutes, strongly dis- 

 coloured, indicative thus of the presence of sulphuretted hydrogen. 



A fourth experiment was made with the blood of a duck. In this instance, 

 instead of emptying the bottle of water before receiving the blood, the water, de- 

 prived of air, was to a certain amount expelled by the blood as it flowed from the 

 divided vessels. The specific gravity of the mixture was 1033. After having 

 been kept from the 23d. of November to the 12th of January, at a temperature 

 varying from about 40° to 50° and 55°, the changes observed on examination 

 were so similar to those already specified that they need not be described. 



A fifth experiment was made with the blood of a fowl. As in the last the 

 blood was mixed with water; but it differed from the last in being subjected 

 to the air-pump as soon as it had become sufficiently cool. No air was thus 

 extricated. The bottle was again closed and inverted in water. This was on 

 the 16th of February; it was examined on the 17th of March. Some difficulty 

 was experienced in withdrawing the stopper. The blood bore marks, of an in- 

 cipient putrefaction ; its smell was offensive, and some muriate of ammonia was 

 formed on a plate of glass moistened with hydrochloric acid put over it during a 

 few hours. 



These results, all so well marked, seem to be nearly identical with those 

 which occur when blood of the same temperature is exposed to the air, almost 

 the only difference that I am aware of being in degree. The change of colour is 

 the same, with the exception, that when exposed to the atmosphere, the blood at 

 the surface, especially if it be venous, becomes florid before it darkens ; the change 

 of form of the corpuscles is the same, and the solution in the serum of their 

 colouring matter. The same gases likewise are formed, and the same alkali is 

 generated, accompanied by the characteristic putrid odour. 



That blood should thus undergo change when air is excluded, is no more, per- 

 haps, than might be expected when we reflect on its composition, and that oxygen 



