DERIVATIVES OF HAEMOGLOBIN. 43 



meter, 38 cc. of water had to be added to obtain the same tint as that of the 

 standard solution, so that the volume of water which would require to be 

 added to dilute the whole 400 cc. would be 1,520 cc., thus 



10 : 400 : : 38 : x 

 x= l,520cc. 



By adding 1,520 cc. of distilled water to the 400 cc. of blood solution, we 

 get 1,920 cc. of the same tint or degree of dilution as the standard solution. 

 The standard solution on analysis was found to contain 0'145 grms. of 

 haemoglobin in 100 cc., so that the total amount of the haemoglobin in the 

 diluted blood is found, thus 



100 : 1,920 : : 0'145 : x 



x = 2 '784 grms. 



Since, however, this amount of haemoglobin was obtained from 20 '186 grms. 

 of the original blood, the amount in 100 parts will be found, as follows: 



20-186 : 100 : : 2'784 : x 

 x 13 '79 grms. per cent. 



8. The Haemoglobinometer of Gowers is used for the clinical 

 estimation of haemoglobin (Fig. 8). The tint of the dilution of a 

 given volume of blood with distilled water is taken as the index 

 of the amount of haemoglobin. The colour of a dilution of aver- 

 age normal blood (one hundred times) is taken as the standard. 

 The quantity of haemoglobin is indicated by the amount of dis- 

 tilled water needed to obtain the tint with the same volume of 

 blood under examination as was taken of the standard. On 

 account of the instability of a standard dilution of blood, tinted 

 glycerin-jelly is employed instead. The apparatus consists of 

 two glass tubes of exactly the same size. One contains (D) a 

 standard of the tint of a dilution of 20 c.mm. of blood, in 2 cc. of 

 water (1 in 100). The second tube (0) is graduated, 100 = 2 c. 

 (100 times 20 c.mm.) The 20 c.mm. of blood are measured by a 

 capillary pipette (B). 



(a) Place a few drops of distilled water in the bottom of 

 the graduated tube (C). 



(b.) Puncture the skin at the root of the nail with the 

 shielded lancet (F), and with the pipette (B) suck up 20 

 c.mm. of the blood, and eject it into the distilled water, and 

 rapidly mix them. 



(c.) Distilled water is then added drop by drop (from the 

 pipette stopper of a bottle (A) supplied for that purpose) 



