426 



VICTOR C. MYERS 



exhibit a relatively high blood volume, while in some cases polycythernia in 

 the sense of a high blood count may be dependent on a low plasma volume. 

 Jn auasarca accompanying myocardial insufficiency the blood volume may 

 be absolutely increased. In many, cases of marked hypertension tho 

 volume is small, indicating that hypertension is not necessarily dependent 

 upon a large blood volume. 



[More recently a very elaborate study of the question of blood volume 

 lias been carried out on animals by Whipple and some of his coworkers. 

 Since "vital red'' was not available, their earlier experiments were made 

 with "brilliant vital red." Later they tried out a very large series of 

 dyes for use in this connection, and discovered a blue azo dye which ap- 

 pears to be slightly superior to the vital red group, especially as regards 

 ease and accuracy of color irnetric readings. In the same series of papers 

 McQuarrie and Davis have employed a method of determining blood 

 volume which consists essentially in reading refractometrically the serum 

 non-protein increase after the intravenous injection of a known amount of 

 acacia or gelatin solution, or a mixture of the two. The results obtained 

 were quite comparable to the dye methods and an acacia method described 

 by Meek and Gasser. 



The most recent publication on blood volume is that of Bock who pre- 

 sents some very interesting data, obtained with the vital red method, on 

 five normal and twenty pathological cases. The constancy of the plasma 

 volume under widely varying conditions is pointed to as a striking fact. 

 Although the plasma volume remains practically normal in polycythemia 

 and anemia, as shown by the table below taken from Bock, the total blood 

 volume is increased in the former and decreased in the latter owing to varia- 

 tions in the cell content 



DATA ox BLOOD VOLUME 



Blood volume methods have been critically discussed by Lamson and 

 Nagayama, but the authors concede that the plasma volume method of 

 Keith, Rowntrfce and Geraghty is as correct as any and the best method 

 at our disposal for most purposes. 



Total Solids. Where a careful quantitative examination of the blood 

 is being carried out, the estimation of the total solids is often of consider- 



