THE BLOOD 



75 



matched, say, at division of 75, the blood contains 75 per cent, of the 

 normal quantity of hemoglobin. 



Annotation. Gower's hemoglobinometer, which may also be used, consists of 

 a measuring pipet, a graduated tube, and a sealed tube containing a standard colored 

 solution. This standard represents the color of a 1 per cent, solution of normal 

 blood. The graduated tube is marked in 100 or more parts, each part representing 

 20 c.c. The capacity of the capillary tube is 20 c.c. Thus, if the blood examined 

 is normal, it will be necessary to add water to mark 100 to make the colors corre- 

 spond. If the blood is not normal, the percentage can be read off from the graduated 

 tube above the diluted blood. 



The pipet is filled in the usual way from a drop of blood collected upon the 

 lobule of the ear of the subject. Wipe away any excess of blood after it has been 

 filled. Then blow the blood drop by drop into the water. Shake this tube gently 

 until a thorough mixture has been obtained. Suck a few drops of distilled water 

 into the pipet and add this amount to the mixture. Place this tube beside the one 

 containing the standard solution. Add distilled water drop by drop until the color 



A B C D 



FIG. 46. HEMOGLOBINOMETER. (Gowers.) 



A, Tube filled with colored fluid; B, tube for mixing blood; C, receptacle for distilled 

 water with dropper; D, pipet. 



of the blood mixture corresponds precisely with that of the standard. Make the 

 reading at this time, the percentage of hemoglobin being indicated upon the grad- 

 uated cylinder. 



5. The Specific Gravity of the Blood. Procure a specific gravity 

 bulb or hydrometer, a cylindric graduated glass tube about 15 cm. in 

 height, a pipet or pointed glass rod, a stirring rod, a glover's needle, and a 

 mixture of benzol and chloroform. Secure a drop of blood in the usual 

 way and allow it to fall into this mixture. If the drop of blood remains 

 in the center of the mixture, its specific gravity equals that of the mixture. 

 If it rises, it is lighter than the mixture, and if it gravitates downward, 

 heavier than the mixture. In the former case, add benzol, and in the 



