July 30, 1915] 



SCIENCE 



141 



In puerperal eclampsia, to mention but 

 one more instance, we also have a condition 

 which is generally strikingly benefited by 

 blood-letting.^^ 



Venesection, then, will probably never 

 again be entirely excluded from medicine, 

 as it was during the last quarter of the past 

 century, nor need we fear that the practise 

 will be again misused. 



PLASMAPHERESIS 



But venesection, like all therapeutic pro- 

 cedures, has certain drawbacks which pre- 

 scribe limits to its use, and these drawbacks 

 are inherent in the very composition of the 

 blood and in the nature of the circulatory 

 apparatus. As is known to all the oxygen- 

 carrying power of the blood resides in the 

 red corpuscles, or erythrocytes, which con- 

 stitute about 36 per cent, of the volume of 

 the blood. These erythrocytes, like other 

 cellular constituents, can be built up only 

 slowly in the body by the hemapoietic, or 

 blood-building, organs. It is apparent, 

 therefore, that the bad effects of overbleed- 

 ing, as formerly practised, must be due 

 mainly to the loss of these cellular elements. 

 Common experience has shown that the loss 

 of too much blood is either immediately 

 fatal, or else is followed by a prolonged ill- 

 ness, recovery from which is often doubtful. 



Reflecting on these drawbacks I con- 

 ceived the idea that the main objection of 

 blood-letting could be obviated by the 

 speedy return into the body of the red and 

 the white corpuscles instead of throwing 

 them away as hitherto has been our custom. 



D. B. Lees, Lancet, February 25, 1911. Also for 

 cases in which blood-letting (either by venesection 

 or by means of leeches) may be advantageously em- 

 ployed, see F. de Havilland Hall, Westminster 

 Hospital Eeports, Vol. 17, p. 1, 1911. 



13 See Zweif Si, ' ' Zur Behandlung der Eklamp- 

 sie," Centralbl. f. Gynakologie, 1895, No. 46. 

 Alexander Strnbell, "Der Aderlass, Eine Mono- 

 graphische Studie," Berlin, 1905. 



The only thing that would be removed from 

 the blood of a person bled in this way 

 would be its fluid part — the plasma. If 

 this method were found to be practicable 

 the value of bleeding would be enhanced 

 and its fleld of application extended. Such 

 a method, if successful, would appear to be 

 advantageous for the patients, not only in 

 those instances in which venesection is per- 

 formed, admittedly with good results, but 

 would also open the way for the withdrawal 

 of fluid when it is desired to decrease the 

 volume of blood in the vascular apparatus 

 or to remove excess of deleterious sub- 

 stances, or where bleeding has hitherto been 

 eontraindieated because of the danger of 

 reducing the oxygen-carrying capacity of 

 the blood, as, for example, in aneurism, or 

 in cardiac decompensation with a low 

 blood count. 



In the work now going on in my labo- 

 ratory, we are still in the stage of experi- 

 mentation and study, but our experiments 

 on animals have proved the feasibility of 

 the method. With the skilful cooperation 

 of my colleagues, Drs. Rowntree, Turner, 

 Marshall and Lamson, a considerable num- 

 ber of experiments on animals have already 

 been made. Our procedure, in a word, is 

 the following. Blood is withdrawn freely 

 from an animal and is prevented from 

 clotting by addition of leech extract; 

 Locke 's fluid in equal volume is then added 

 to the blood, and the mixture is sedimented 

 in the centrifugal machine until the cor- 

 puscles have settled out in the flasks. The 

 supernatant plasma is then drawn off and 

 replaced by Locke's fluid, the corpuscles 

 are stirred up and the new mixture is re- 

 turned to the animal. By repeating this 

 process it has been learned that blood- 

 letting can be carried out repeatedly, with- 

 out endangering the life of an animal, 

 provided only that the cellular elements of 



