APPENDIX. 



289 



Mode of counting the blood corpuscles. In 



order to separate the corpuscles and prevent coagulation, 

 the blood used is first diluted to a definite extent say a 

 hundred times with a 10 per cent, solution of sulphate 

 of soda. The mixing can be performed in a measuring 

 glass if the blood is in sufficient quantity, but if only a 

 small drop is obtainable, snch for example, as is got by 

 pricking the finger, the mixer shown in Fig. 36, B, may 

 be used. This consists of a capillary tube terminating 



Fig. 36. 



Malassez's apparatus for counting the blood corpuscles. 



A, Capillary tube for receiving the diluted blood ; B, pipette for m'.xing a 

 small quantity of bio >d with the diluting fluid 



in a bulb, the capacity of the bulb between the marks I 

 and 101 being exactty 100 times that of the tube from its 

 point to the mark 1. A small glass ball is inclosed in 

 the bulb, and serves by its movements to facilitate the 

 mixing. The capillary tube is allowed to fill with blood 

 as far as the mark 1 ; sulphate of soda solution is then 

 sucked up as far as the mark 101. As it passes in, it of 

 course pushes the blood before it into the bulb, and the 

 two are there thoroughly mixed by gentle agitation. 

 The next thing is to count the corpuscles in a known 

 25 



