ESTIMATION OF THE RED CORPUSCLES 235 



polyuria, or any disease in which there is a great loss 

 of water, the blood may be temporarily concentrated, 

 and the amount of haemoglobin (and of red corpuscles, but 

 not of leucocytes, or not to a proportionate extent) may 

 appear to rise. Discount this in giving a good prognosis in 

 septic conditions from the increase in the haemoglobin. A 

 similar concentration may occur from mitral disease or 

 venous stasis from any cause. 



3. A fall in the amount of haemoglobin in a case watched 

 from day to day may indicate haemorrhage, and is occasionally 

 valuable in the differential diagnosis of internal haemorrhage 

 e.g., in cases of ruptured tubal gestation. 



4. In malaria there is a fall in the amount of haemoglobin, 

 very rapid and sudden in the early stages, and often marked, 

 though less rapid, in the later ones. The fall is often to an 

 extent only equalled in acute sepsis. This may be of much 

 diagnostic value. In typhoid fever and in the other diseases 

 for which malaria may be mistaken the anaemia is usually 

 developed much more slowly, if at all. 



ESTIMATION OF THE RED CORPUSCLES 



The best apparatus for the estimation of the number of 

 corpuscles (whether red or white) is the Thoma-Zeiss or 

 Thoma-Leitz haemocytometer. It is usually provided with 

 two pipettes, one for counting the red corpuscles and one 

 for the leucocytes. The latter is rarely used and need not 

 be procured. 



Examine the pipettes. Each has a small bulb containing a 

 little glass ball, and a stem which is graduated into several 

 parts below the bulb, and has a single transverse graduation 

 above it. 



The pipette intended for use in counting the leucocytes 

 may be distinguished by the fact that it has the figure n over 

 the single transverse graduation above the bulb. 



There are two forms of pipettes made for counting the red 

 corpuscles. In the one the stem below the bulb is divided 

 into ten parts, the upper one (nearest the bulb) being marked 

 i, and the middle one 0-5 (Fig. 46, S). In the other the same 

 portion of the stem is graduated into three portions num- 

 bered fiui T!O> and <&$ ; the figure mentioned first is placed 



