A method of studying the effect of serum upon tissues

Abstract

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 Abderhalden 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 recently 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 microscopic 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.