20 



QUANTITATIVE ESTIMATION OF HAEMOGLOBIN. 



" Since average normal blood yields the tint of the standard at 100 degrees of dilution, the 

 number of degrees of dilution necessary to obtain the same tint with a given specimen of blood 

 is the percentage proportion of the haemoglobin contained in it, compared to the normal. For 



instance, the 20 cubic millimetres 

 of blood from a patient with anae- 

 mia gave the standard tint of 30 

 degrees of dilution. Hence it 

 contained only 30 per cent, of the 

 normal quantity of haemoglobin. 

 By ascertaining with the hema- 

 cytometer the corpuscular richness 

 of the blood, we are able to compare 

 the two. A fraction, of which the 

 numerator is the percentage of 

 hemoglobin, and the denominator 

 the percentage of corpuscles, gives 

 at once the average value per cor- 

 puscle. Thus the blood mentioned 

 above containing 30 per cent, of 

 haemoglobin, contained 60 per cent, 

 of corpuscles; hence the average 

 value of each corpuscle was g# or ^ 

 of the normal. Variations in the 

 amount of haemoglobin may be re- 

 corded on the same chart as that 

 employed for the corpuscles. The 

 Fig. 14. instrument is only expected to 



Gowere' hamoglobinometer. A, pipette bottle for distilled y\ d approximate results, accurate 

 water ; B, capillary pipette ; C, graduated tube ; D, tube within 2 or 3 per cent. It has 

 with standard dilution; F, lancet for pricking the linger, however, been found of much 



utility in clinical observation. J 

 () Fleischl's HaBmometer. For clinical purposes this instrument (tig. 15) is useful. A 

 cylinder <", of two compartments a and of, rests on a metallic table. Both compartments are 



filled with water, but in one (a) is placed 

 a known quantity of blood measured in 

 a measuring-tube of known capacity. 

 The red colour of the solution of haemo- 

 globin thus obtained is compared with 

 a red wedge of glass (K), which is moved 

 by means of a wheel (R and T) under 

 the other compartment (a') until the 

 two colours are identical. The illumina- 

 ation of the dilute blood solution and 

 the red glass wedge is done from below 

 by lamp light reflected from the white 

 reflecting surface (S). The frame in 

 which the red glass wedge is fixed bears 

 numbers, and when the colour is iden- 

 tical in the two compartments a and a', 

 the percentage of haemoglobin as com- 

 pared with normal blood can be read oft* 

 d irectly. Suppose it to be 80 on the scale, 

 then the blood examined contains 80 per 

 cent, of the hemoglobin of normal blood. 



The amount of haemoglobin in 



man is 13*77 per cent, in the 



woman 12*59 per cent., during 



Eldiehl't hmnometar. K, red coloured wedge of pregnancy 9 to 1 2 per cent ( Preyer). 



glass moved by K; <;, mixing .vessel with two According to Leichtenstern, Hb is 



i oni|artmeuts a and a'; M, table with hole to read i n greatest amount in the blood of 



a newly-born infant, but after ten 

 weeks the excess disappears. Be- 

 tween six months and five years it is smallest in amount ; it reaches its second 

 highest maximum between twenty-one and forty-five, and then sinks again. From 



>tl the percentage of haemoglobin on the scale P 

 T, to move K ; B, mirror of plaster of Paris. 



