THE CLINICAL PATHOLOGY OF THE BLOOD 

 OF DOMESTICATED ANIMALS 



CHAPTER I 

 METHODS OF EXAMINATION 



Ordinarily a clinical examination of the blood consists of count- 

 ing the red and white corpuscles, obtaining the amount of hemo- 

 globin, and making a histological examination of stained speci- 

 mens. Occasionally other information is desired, as the total 

 volume of blood and its oxygen capacity, the relative volume of 

 corpuscles and of plasma, the number of blood plates, the specific 

 gravity, the time of coagulation, the presence of specific agglutinat- 

 ing or precipitating substances, and the presence of parasites. 



Procuring the blood. Blood may be procured from any part 

 of the body where the circulation is normal. Inflamed or edema- 

 tous areas are especially to be avoided. A cold or bloodless part 

 is unsuitable. If a cold part is warmed, sufficient time should be 

 given to allow the circulation to become normal before procuring 

 blood for examination. In the horse and cow the under side of 

 the tail where free from hair, slightly to one side of the median 

 line to avoid the middle coccygeal artery, is a convenient site, or 

 if preferred, the rump or the side of the neck may be chosen; in 

 smaller animals the lobe of the ear will be found suitable; in the 

 domestic fowl the comb and in the pigeon the under surface of the 

 wing are easily accessible and convenient. 



Preparation of the site. The part from which blood is to be 

 obtained should be washed with water, in the larger animals 

 where the incision is to be made with a fleam, disinfected, and 

 then dried with alcohol. Vigorous rubbing of the part should be 

 avoided as it produces a transient local change in the blood. In 

 case the neck, or other part in the horse or cow having long hair, 

 is selected the hair may be parted and the skin, exposed in the 



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