144 



SCIENCE 



[N. S. YoL. XLII. No. 1074 



TABLE III 



Continued Plasmapheresis on a Dog for Five Suc- 

 cessive Days 



Esp. No. 6, Jan. 22 to 26, inclusive. A before 

 plasmapheresis, B after plasmapheresis. 



Weight of dog 8.5 kg. Estimated blood volume 

 (7.5 per cent.) =640 c.c. Total blood removed 

 in five days, 3,335 e.c. = 521 per cent. Analytical 

 results in percentage of total blood. 



The results obtained in continued 

 plasmapheresis are shown in Table III. 

 The amount of blood taken was about one 

 volume on each day. The first two columns 

 of analytical results, obtained with samples 

 taken at the beginning and end of the day 's 

 work, compare closely with those in Table I. 

 The third column shows the results at the 

 end of the third day's work, when the 

 plasma protein reached the lowest value, 

 2.23 per cent. The fourth column gives the 

 results at the end of five days of plasma- 

 pheresis, while the last column shows the 

 results twenty-four days later. Here the 

 plasma protein has gone up again nearly to 

 its original value. The corpuscle protein, 

 and consequently the total protein, also, are 

 low, owing to the anemia. 



VIVIDIFFUSION 



I should like now to describe a second 

 method for the study of the blood, and to 

 state briefly some of the results that have 



Influence of Plasmapheresis on Blood Pressure 

 Mean Systolic Pressures in Millimeters of Mercury 

 Exp. No. 6, Jan. 22 to 26, 1915, inclusive. 



Day of 

 Expt. 



Volume 

 Bled, 

 C.c. 



2d 



3d 



250 

 250 

 170 



200 

 125 

 170 



195 

 210 

 200 

 185 



205 

 200 

 200 

 135 



180 

 190 

 175 



Bleeding 



Before Afte 



208 

 115 

 140 



165 

 65 

 65 



202 

 185 

 115 



pressures not observed on this day. 



110 

 110 

 110 

 105 



110 



100 



80 



75 



100 



65 



47 



1 hr. later = 



135 

 120 

 105 

 105 



110 



105 



95 



110 



already been obtained by its use. But first 

 let me remind you that there are numerous 

 constituents of the blood derived from 

 various organs which are of the most vital 

 significance to the economy and which are 

 present in the blood in only minute quan- 

 tity at any one time. Among these as yet 

 unidentified substances, which nevertheless 

 are certainly known to pass from one organ 

 to others via the blood, are all of the so- 

 called hormones, the active principles of the 

 organs of internal secretion. Of these 

 organs I shall presently speak more in de- 

 tail. 



Our present methods of blood analysis 

 give us little help when we endeavor to 

 isolate and identify one of these elusive 

 yet vitally important principles, not to 

 mention other substances of the greatest 

 interest arising in the intermediary stages 

 of metabolism. 



Pondering over this problem, it occurred 

 to me that possibly one might construct an 

 apparatus which could be attached to the 

 blood vessels of a living animal and re- 



