818 Experiments 



And so, as a result of compression, when the experiment has 

 been well conducted, the blood is preserved without putrefying, 

 both in the compressed air, and on being removed from the com- 

 pressed air. The only change consists of the varnished appearance 

 which it takes on, due to the fact that the hemoglobin leaves the 

 corpuscles and is dissolved in the serum. This always occurs, 

 moreover, in dead blood, and even in blood which has putrefied 

 in closed vessels, after the putrid fermentation is over. 



Not only are the vibriones killed thus before beginning their 

 work, but when blood in the process of putrefaction is compressed, 

 the putrefaction ceases, and the characteristic odor decreases to 

 the point of disappearing. 



But experiments on blood present a difficulty about which I 

 should like to say a few words now, because it caused failure in a 

 number of my experiments at the beginning, and because it might, 

 if I did not mention it, cause uncertainty in the minds of those 

 who would like to run control experiments on my work. 



I often saw blood which had kept well in the apparatus decay 

 rapidly at normal pressure, even in vessels carefully closed by the 

 flame. When I examined these data carefully, I found that this 

 happened only in experiments made in tubes, never in those made 

 in matrasses. This peculiarity results, as I suspected immediately, 

 from the fact that the thickness of the layer of blood is different in 

 the two operative methods. 



I then perceived that oxygen, even at the highest tensions, pene- 

 trates the blood only a little way. Example: 



Experiment CCCCXVII. December 2. 100 cc. of blood are placed in 

 a test tube with a foot; they rise to a height of 10 cm.; compression 

 in the mercury bottle to 20 superoxygenated atmospheres. 



December 6. Instantaneous decompression; very little gas escapes 

 from the liquid; no froth. 



The floating serum rises to a height of 3 cm.; below is a layer 

 of very red blood 3 cm. thick; the rest of the blood is quite dark. 



It is then quite evident that there can be an excess of oxygen 

 only in the superficial layers of the liquid, and that consequently 

 vibriones in the deep layers will not be affected by the oxygen, or 

 at least only slightly. Thence arises the putrefaction which ap- 

 pears more or less quickly, and which in one case I saw appear 

 during the compression; the variations result from many circum- 

 stances in the multiplicity of which the height of the column used 

 stands out definitely. One should never use blood in a thickness 

 of more than a half-centimeter, if one is to be absolutely certain 

 of succeeding. 



