696 
PROFESSOR HARLEY ON THE INFLUENCE OF 
but only with red coagulum was it found sufficiently well marked to merit being noticed 
here. Three equal portions of coagulum from fresh ox-blood were confined with 100 
per cent, of atmospheric air during six hours at the following temperatures. 
(a) At 21° C. ; ( b ) at 30° C . ; (c) at 36° C., with the following results: — 
Amount of carbonic acid in 100 parts of air in 
No. 17. ( a ) 6 hours at temperature of 21° C.=2-34 carbonic acid. 
No. 18. (b) „ „ 30° C.=5T8 
No. 19. (c) „ „ 36° C.=7-29 
It is thus seen that the amount of carbonic acid exhaled by red-blood coagulum in- 
creases with the temperature as far as the experiment went, namely from 21° to 36° C. 
2nd. As regards the influence of cold in retarding the reciprocal chemical changes 
which occur between atmospheric air and blood, a striking proof of which is to be found 
in the result of the following experiment. 
Two ounces of arterial blood were allowed to flow directly from the carotid artery of a 
dog into a glass receiver, which in order still further to ensure its being thoroughly oxi- 
dized, as well as to prevent its coagulating into a solid mass, was shaken with renewed por- 
tions of air during two hours ; a small quantity of fluid mercury being also employed to 
prevent the coagulation. After this treatment the receiver was firmly corked and kept 
(with occasional agitation) in a room the temperature of which never exceeded 7° C. 
during five whole days. 
Dog’s arterial blood five days at a temperature under 7° C.* Result: 
-In 100 parts of air. 
12-62] 
^ 9 |Total oxygen 14*34 
No. 20.- 
Oxygen . 
Carbonic acid . 
Nitrogen . . . 85-66 
On its removal from the receiver, the blood, although dark in colour, had a perfectly 
fresh odour. The diminished temperature not only retarded the chemical changes, which 
for the sake of convenience we may term “ respiratory,” but also those decompositions 
and transformations so intimately connected with oxidation, to which the name “ putre- 
faction” has been given. 
(e) Influence of the age of the blood. 
The putrefactive changes occurring in blood are exceedingly curious, and perhaps it 
may not be out of place if some of them be here alluded to. 
The following series of experiments were made on sheep’s blood. The first began 
within two hours after the blood was withdrawn from the animal, the last after it had 
stood 688 hours. 
* The first part of this experiment has been already given, but it is here again repeated in order to save the 
time of the reader in referring back to it, and so it is occasionally done with some others. 
