42 A Manual of Veterinary Physiology. 



presence in blood (60 per cent, to 90 per cent, of the total 

 amount of ash) corresponds to its importance. As the 

 blood is simply the carrier of the salts, and the only means 

 by which the tissues can obtain them, it by no means 

 follows that all the mineral matter found in it is essential 

 to its own repair and constitution. 



The Quantity of Blood in the Body can only be estimated 

 approximately ; direct bleeding alone does not furnish us 

 with a true result ; after all the blood is drained on\ the 

 vessels require to be washed out, and the quantity of blood 

 in the water estimated by the colour present ; the body 

 has then to be minced and macerated, and the quantity 

 of blood in this estimated by the colour test, comparison 

 being made with a standard solution of blood. 



According to Colin the weight of blood in the body of 

 oxen is 39 lbs. ; horses, 47 lbs. (35 '2 pints) ; sheep, 41 lbs. : 

 pigs, 3 lbs. Sussdorf,* quoting recent experiments, puts the 

 proportion which the weight of the blood bears to the body 

 weight as being, for the horse, T V 7 ; sheep, r \; pig, .\, : <>x. ','... 



The same observer quotes the amount of blood in the 

 body of the horse at 66 lbs., or nearly .50 pints. 



The Distribution of Blood in the Body, according to 

 Ranke, is as follows : 



About one-fourth in the heart, lungs, large vessels, and veins. 

 „ „ liver. 



,, ,, skeletal muscles. 



,, ,, other organs. 



It is probable that in the horse the liver would contain less 

 than one-fourth the bulk of blood, whilst the skeletal 

 muscles would contain more. 



The abdominal veins are capable of containing the 

 whole of the blood in the body. When an organ is active, 

 it receives from 30 per cent, to 50 per cent, more blood 

 than when at rest (M'Kendrick). 



The Gases of Blood.— The blood gases are obtained by 

 introducing the fluid into a Toriccllian vacuum, the in- 

 strument used to obtain it, being a mercury pump. In a 

 * Ellenbergef's ' Physiologic der Haussaugethiere.' 



