I22 THE JOURNAL OF PHARMACOLOGY. 



SOME CLINICAL METHODS OF EXAMINING THE BLOODS 



By Thaddeus Walker. M. D., Detroit, Mich. 

 Microscopist to Harper Hospital. 



Hematology, or the study of the blood, a comparatively new branch of 

 scientific medicine, is already too exhaustive in scope to be dealt with 

 fully in the short time allotted this paper. It is, therefore, my purpose 

 this evening to consider only a few of the more important methods of 

 examining the blood, which are to-day of value to the clinician. 



It is very valuable in many cases to know if the corpuscles are di- 

 minished in number. For this purpose the Thoma-Zeiss corpuscle counter 

 approaches nearer exactness than any other method yet devised. The 

 principle of this instrument is an actual count with the microscope of the 

 corpuscles in a known dilution of blood. 



Technique. — We first prick the lobe of an ear or a finger, and as soon 

 as the blood flows freely we insert the end of the tube in the drop, and 

 then gently but steadily suck upon the mouthpiece at the end of the rub- 

 ber tubing, care being taken not to admit any air. We fill the tube com- 

 pletely up to the mark 0.5; if we go a little beyond, some may be drawn 

 back by means of blotting paper, but this is not recommended when we 

 have gone over one-thirty-second of an inch beyond the mark. "We now 

 quickly wipe away any blood on the outside of the tube, place the end in a 

 diluting solution, 1 immediately begin to suck some of this up into the 



Diluting solution for red blood corpuscles. 



Hydrargyii bicMor 0.5 



Sod. sulph 5. 



Sod. chlor 2. 



Aquae destillat 200 



Mi see. 



bulb, rotating the tube at the same time, so as to mix the blood and so- 

 lution and fill up to mark above bulb. We now blow out the diluting 

 solution in the tube which is not mixed with blood, and allow a small drop 

 from the bulb to flow onto the island in the slide. We next place a cover- 

 glass over the drop, but if the drop be too large some will run over into the 

 moat, which necessitates our cleaning the slide and trying another drop; 

 practice teaches us about the size of drop to cover the island, or at least 

 nine-tenths of it. If we have filled the tube with blood up to 0.5 mark 

 and with solution to mark beyond bulb, we have a dilution of 1:200. We 

 now place slide under microscope and focus upon the fine rulings on the 



* Read before the Detroit Academy of Medicine. 



