QUANTITATIVE ESTIMATION OF THE HEMOGLOBIN. 53 



of metallic iron found, the percentage of hemoglobin in the blood will be as 100 

 m : 0.42. The mode of procedure is as follows: A measured amount of blood is 

 reduced to ash and this is exhausted with hydrochloric acid for the preparation 

 ot tcrnc chlond. Next the ferric chlorid is converted into ferrous chlorid and 

 this is titrated with a solution of potassium permanganate. 



(6) Colorimelric Method. A dilute watery solution of crystallized hemoglobin 

 is prepared, the exact strength of which is thus known. With this are compared 

 watery dilutions of the blood to be examined, water being added to the latter 

 until the color is the same as that of the hemoglobin-solution. The specimens to 



FIG. ii. -V. Fleischl's Hemometer. To wash out the graduated pipet the larger tube held over it is employed. 



be compared are contained in similar vessels of exactly the same thickness (hema- 

 tinometer). Hoppe-Seyler has recently devised a colorimetric double pipet for 

 this purpose. The blood-specimens are saturated with carbon monoxid. 



For clinical purposes v. Fleischl's hemometer is recommended (Fig. n). This 

 consists of a cylinder mounted upon a metallic plate and divided into two equal 

 parts, which are closed at one extremity by a disc of glass. Each half is filled 

 with water, and then a measured amount of blood, obtained with a pipet of deter- 

 mined capacity from a punctured wound, is introduced into the one half and 

 dissolved. The color of the red solution thus produced is compared with that of 

 a ruby-red glass wedge viewed through the clear water in the other half of the 

 cylinder and capable of being moved forward and backward by a screw, until 



