78 



Scientific Proceedings (57). 



sulphate or acetone, the latter by extracting the castor bean prepa- 

 ration with 1.5 normal sodium chloride solution and removing 

 the salt by dialysis. 



It is interesting to note that the different lipases found in 

 extracts of animal organs, are present in the duodenal contents of 

 human beings and may also be obtained from a vegetable sub- 

 stance such as castor beans. 



46 (863) 



Modifications of the Abel vividiffusion apparatus. 



By W. G. MacCallum, M.D. and R. A. Lambert, M.D. 



[Department of Pathology, College of Physicians and Surgeons, 

 Columbia University, New York.] 



The apparatus for the study of the circulating blood by a 

 process of diffusion devised by Drs. Abel, Rowntree and Turner 

 has impressed us as such a brilliant stroke of inventive genius that 

 we have hastened to imitate it and apply it. The scope of this 

 method is perhaps not yet fully appreciated, but it has interested 

 us particularly in affording a hopeful way of studying the inorganic 

 constituents of the blood, especially in connection with tetany 

 where we think that calcium plays a considerable role. The 

 results of these experiments are as yet entirely incomplete but we 

 wish to describe several modifications in the technique which may 

 have been tried and discarded by Dr. Abel but which seem to us 

 to be helpful. 



The branched glass end pieces which allow the current of blood 

 a choice of several paths are extremely difficult to make and are 

 very fragile. Unless they are made very precisely, one path be- 

 comes easier than another in which blood may circulate slowly or 

 stagnate. With this arrangement blood passes once only through 

 the length of the apparatus and back again, but since the stream 

 bed, with these many possible channels, is very wide, the current 

 must be relatively slow. 



We have constructed two or three machines in which the blood 

 circulates back and forth eight or ten times before returning to 

 the vein. In the first model the connections were made as in a 



