2 METHODS OF EXAMINATION 



parting, washed as indicated. It is not ordinarily necessary to 

 shave the site. 



Puncture. In the larger animals it is advisable to use a fleam 

 or a scalpel for making the puncture as a blood lancet does not 

 yield sufficient blood. In the smaller animals a blood lancet or 

 straight surgeon's needle is preferable. Whatever instrument is 

 used should be sharp. A dull needle or fleam causes more pain 

 and affords less blood than one that is sharp. In the domestic 

 fowl blood may be readily and easily secured by snipping off the 

 tip of one of the points of the comb. 



Securing the blood. Before making the puncture whatever 

 apparatus or material is to be used should be ready and within 

 reach so that there may be no unnecessary delay in securing the 

 blood for examination. Slides for making smear preparations, 

 the hemoglobinometer and the pipette for making the dilution 

 should be clean and within reach. The bottle of diluting fluid 

 should be unstoppered. A towel or clean cloth should be at hand. 

 After the puncture is made the first three or four drops of blood 

 should be wiped off. Then freshly exuded blood should be secured 

 for examination, for counting the red corpuscles and leucocytes, 

 for obtaining the hemoglobin value, for making smears for his- 

 tological examination or for other kinds of examination. The 

 more rapidly blood is secured for these several processes the 

 better. Blood quickly changes when exposed to the air. Clotted 

 blood is wholly unsuitable and even before it clots blood undergoes 

 certain changes, some of which simulate changes found in patho- 

 logical conditions. Blood should be obtained as nearly as possible 

 in the condition in which it is in the blood vessels. After sufficient 

 blood has been secured the edges of the wound in the larger ani- 

 mals should be held together for a few seconds until they adhere. 

 On the following day it will require careful search to find the 

 wound. 



COUNTING THE RED CORPUSCLES 



The red corpuscles are so numerous in the blood that it is neces- 

 sary to dilute it considerably to be able to count them. The 

 i liluting fluid must be of such a nature that it will prevent coagula- 

 tion, will not change the corpuscles and should be of such a specific 

 gravity that the corpuscles will settle, not too rapidly or it will be 



