the Optical Rotation of the Proteins of Blood Sera. 179 



in the paper cited, the later effort has been directed to a study of the proteid 

 components of serum and their individual influence on the spectrum. For 

 this, the Beit Research Fund Committee of the British Homoeopathic 

 Association have again given generously the necessary financial aid out of the 

 funds placed at their disposal by Mr. Otto Beit for purposes of scientific 

 research. 



A search in the literature has failed to reveal any information on the subject, 

 so that in all parts of the work it was necessary to break new ground. Two 

 papers on " Ultraspectroscopic Studies in Blood Serum," one by T. Tadokoro 

 and the other by T. Tadokoro and Y. Nakayama, appeared in America in the 

 ' Journal of Infectious Diseases ' for Jamiary, 1920 (vol. 26, pp. 1 to 7, and 8 

 to 15), and recall the subject matter of the first paper cited, but they do not 

 in any way anticipate the present communication. 



It has already been observed that the absorption band of serum is caused 

 entirely or almost entirely by the proteins contained, and it became a matter 

 for inquiry as to whether the albumin, pseudo-globulin and eu-globulin were 

 similarly or variously absorbent of ultra-violet light. 



The necessary preliminary to a spectroscopic examination of these com- 

 ponents was to separate them in a pure state, and to devise means for deter- 

 mining the concentration of the solution employed. This proved an 

 unexpectedly difficult task, partly because of the confused state of the informa- 

 tion available and partly because of the necessity of employing solutions perfectly 

 free from preservatives and other substances capable of affecting the spectrum- 

 absorbing power of the solutions. In the end there was no alternative to 

 relying on one's own discretion and to devising the details of the processes 

 of separation and purification. Great care was exercised with a view to purity 

 and constancy of product. 



In formulating the processes, much attention was paid to those published 

 by Hardy, Hartley and Haslam, but more particularly to the researches of 

 Dr. Flarriette Chick on the physical conditions which control the precipitation 

 of the proteins of serum, published in 1913 and 1914 in the ' Biochemical 

 Journal.' 



Method of Separating the Proteins. 



In the processes of separation ammonium sulphate was practically the only 

 reagent employed. The purest qualities obtainable commercially were 

 carefully tested for organic matter, as traces of this would affect the absorption 

 spectrum, and the best specimens were selected. 



The manner of procedure was in principle such as that usually followed, 

 depending on suitable application of various concentrations of ammonium 

 sulphate ; but numerous details were carefully studied, and amongst these the 



