On the behavior of the mammalian ovary and especially of the atretic follicle towards vital stains of the acid azo group

I have given elsewhere 1 a description of those cells of the mammalian body which react so predominantly even if not in a wholly specific way with vital dyes of the acid azo series as to justify their recognition as a great functional unit or cell class. For the cells in question it is suggested that we retain the old term macrophage, which although proposed by Metchnikoff without the kind or the complete extent of evidence now available for delimiting the class, nevertheless puts in the foreground their salient structural and functional peculiarity and has the further advantage of enabling us to coördinate these studies with those long made by the comparative pathologist.

It is worthy of note that in some of those cases of local tissue degeneration and death which one must regard as physiological or normal, the macrophages must, in analogy with the experience of pathologists, be actively concerned. This above all is exemplified by the cyclic changes undergone by the mammalian ovary. The strange cells which since the time of Pflüger have been known to be of assistance in atresia of the follicle and whose derivation from granulosa or theca or from leucocytes, i. e., from practically every available source, has in turn been championed—are picked out by the azo dyes so brilliantly and so electively as to preclude the denial of their alignment as typical macrophage cells guinea pig, rabbit, dog and monkey, in the latter of which the conditions are so similar as to stand for the case in man.

Striking as they are, these studies are not sufficiently indicative of the altogether unusual affinity of the atretic ovum macrophages for these dyes, a fact which forces itself on our attention when small doses of the dyes are given.