Effect of Serum upon Tissues. 



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114 (1046) 



A method of studying the effect of serum upon tissues. 



By S. Feldstein, M.D. 



[From the Department of Experimental Therapeutics, Cornell 

 University Medical College.] 



In the investigation of the action of serum ferments on animal 

 tissues chemical methods have been almost exclusively used. 

 Within the last few years the dialysis method developed by Abder- 

 halden has been extensively employed in experimental as well as 

 clinical investigations. While the technique of this method is not 

 as difficult as it is usually assumed to be, at every step of the 

 procedure a not inconsiderable number of errors are likely to 

 creep in. It requires very careful preparation of the substrate, 

 absolutely uniform dialyzing tubes and great care in boiling the 

 dialysate. 



The most weighty objection to the dialysis method, however, 

 lies in the fact that it gives only indirect evidence of the enzymatic 

 action of the serum on the tissue. It is due to this fact that re- 

 cently Bronfenbrenner and others have claimed that a positive 

 Abderhalden test does not show the proteolytic action of the 

 serum on the tissue substrate at all, but that during the incubation 

 of the serum with tissue, the antiferment of the serum becomes 

 adsorbed. The removal of the antiferment exposes the serum 

 proteins to the action of the ferments in the serum and it is their 

 cleavage products which pass into the dialysate and give the 

 positive reaction. 



Considerations of this nature led the author more than a year 

 ago to seek for a method of demonstrating the ferment action of 

 serum in the histologic examination of tissues. A priori it was 

 to be expected that early evidence of the chemical changes resulting 

 from ferment action might be shown by alteration in the micro- 

 scopic appearance and staining reaction of the tissue. 



Almost the first specimen examined, that of a boiled guinea-pig 

 placenta exposed to the action of normal and pregnant guinea-pig 

 serum, having fortunately shown a most remarkable difference, 

 the author was encouraged to continue the investigation. Soon 



