BLOOD. 193 



Arterial blood, on being Avliipt, allows the fibrin to separate 

 in short conglobate masses, more tenacious and compact than 

 the fibrin of venous blood. 



The odour of arterial Ijlood is considered to be stronger than 

 that of venous. The temperature is also usually stated to be 

 different, Jurine being the only experimentalist who assigns an 

 equal temperature (i. e. 103°-2) to both forms of blood. Ac- 

 cording to Scudamore the temperature of arterial blood in man 

 is 1°'8, according to Kramer 2°-7, higher than venous blood. 

 Dr. Davy found the difference in animals amount to 3°'6. The 

 observations of Colemann, Cooper, and Martini are directly 

 opposed to the above statement. (Lecanu, Etudes chimiques 

 sur le Sang.) 



The relative capacity for heat of arterial and venous blood 

 is, according to Davy, as 839 to 852. 



There is considerable difference of opinion among physiolo- 

 gists with respect to the specific gravity of arterial and venous 

 blood : Hammerschmidt, Davy, Scudamore, and Letellier assert 

 that the density of arterial is lower than that of venous blood ; 

 the former being represented by 1039*8 — 1042-9, the latter by 

 1053—1056. 



the easy passage of the whole light through it ; moreover, on account of its attenu- 

 ation, it bursts, and allows of the escape of its contents, as may be observed on the 

 addition of water to red blood. If the blood remain in contact with water till a dark 

 tint becomes apparent, and a saturated solution of a neutral salt be then added, the 

 corpuscles again become biconcave, in consequence oftheir being partially emptied by 

 the endosraosis called into play by the different fluids within and without the capsule ; 

 and the capsules themselves, and the original bright red colour reappear. A current of 

 carbonic acid gas passed through fresh red blood renders the corpuscles biconvex, 

 and makes the blood assume a dark venous hue. 



Mulder explains the diiference between the coloiu- of arterial and venous blood in 

 the following manner : Two oxides of protein are formed in the act of respiration ; 

 they have a strong plastic tendency, and solidify round each corpuscle, making the 

 capsule thicker and better qualified to reflect light. Each corpuscle of the arterial- 

 ised blood is then in reality invested with a complete envelope of bufiy coat, which 

 gradually contracts, and speedily forms the cupped or biconcave surfaces, which, as 

 we have already shown, are favorable to the reflection of hght. On reaching the 

 capillaries, the coating of the oxides of protein is removed, and the corpuscles, losing 

 their opaque investment and their cupped form, can no longer reflect light, and the 

 blood assumes a venous tint. (Mulder's Versuch einer allgemeinen physiologischen 

 Chemie, pp. 344-59 ; or Dr. G. Bird's account of Mulder's Researches, in the Medical 

 Gazette, December 1844.) 



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