430 MINOT. [Vo. II. 
ory cannot be accepted definitely until verified by further obser- 
vations on normal uteri. Overlach found in the cervix of the 
uterus in question, the lining epithelial cells to contain an en- 
dogenous brood of small cells, one to fifteen in each parent-cell ; 
the daughter-cells begin as nuclei, around which there gathers 
a protoplasmatic body for each. The cells are like the young 
decidual cells just below, so that the latter may be assumed to 
have wandered forth from the epithelium. I may recall that in 
the normal menstruating uterus I find no true decidual cells, 
and consequently I must regard Overlach’s find as pathological. 
The observations of Creighton, of Masquelin and Swaen, and 
of myself may be fairly considered to establish the fact that in 
rodents, at least, the decidual cells arise from the connective 
tissue cells of the mucosa. That they arise from the same cells 
in man is rendered extremely probable by the investigations of 
Leopold, which have been confirmed and extended by the obser- 
vations recorded in §§ 16, 17, and 18, of the present article. 
Accordingly I assent to the second of the views above enumer- 
ated. 
Ercolani erroneously regarded the decidual tissue as a new 
formation, arising after the total destruction of the mucosa. He 
observed the degenerative processes of the uterine epithelium, 
and the arrangement of the decidual cells around the vessels of 
the placenta in rodents and other mammals; he inferred that 
the whole mucosa was degenerated and lost, but he never estab- 
lished the inference by observation; he also inferred that the 
perivascular cells, being different from the surrounding tissues, 
were a new formation, but he never traced the actual genesis of 
the cells. In spite, however, of the absence of the observations 
necessary to establish his double thesis of the total destruction 
of the mucosa and the new formation of the decidua, he advo- 
cated his doctrine with the greatest earnestness, even to the 
last — see 91, 92. The failure of his hypothesis to find accept- 
ance has been due not to any unreadiness to bestow merited 
acknowledgment upon his researches, but to the incompatibil- 
ity of the hypothesis itself with the ascertained facts of the 
structure and development of the placenta. While, therefore, 
we utilize Ercolani’s numerous and valuable observations, it will 
be a distinct gain for science to set aside his theory of the new 
formation of the decidua. 
