Basil C. H. Harvey 233 
in full the contentions of Bard, 98, who believes that there is inherent 
in the cell by its heredity a predestination to a certain form and function 
unalterable by the action of external conditions except within the nar- 
rowest limits. But it indicates that cells, which from whatever cause, 
either inherent or external, have reached a certain stage of differentiation 
and specialization, do not possess the power to respond readily to the 
action of external influences. They tend to retain the form and function 
which they have attained, even when subjected to the action of external 
conditions very different from those which have previously been acting 
upon them. The ferment cells, however, though very highly specialized, 
frequently in response to changed conditions assume a form through 
which they have probably passed during the development of their 
special characters. This retrograde step is not necessarily a degeneration 
or final differentiation, for they possess still a tendency on the removal 
of the disturbing conditions to become again specialized. And _ this 
further development tends to proceed by lines along which the cell has 
previously travelled in its cytomorphosis. ‘'To this extent my observations 
show that such highly differentiated cells possess a kind of specificity. 
But the tendency to develop along such lines is not an imperative necessity 
to the cell. It retains the power of developing along other lines also, 
if certain other external conditions be present, and the number of trans- 
formations presented by gastric chief cells is very considerable. Schmidt, 
96, reports that he found these cells changing into intestinal epithelium 
consisting of goblet cells and cylindrical cells with a striated cuticle, at 
the margins of ulcer and in chronic inflammation. Leuk, 99, found 
goblet cells among them. Hari, o1, reports them in both healthy and 
pathological conditions in various parts of the human stomach, often 
in the fundus region. Schaffer also reports the existence in the human 
stomach of similar patches of intestinal epithelium which he regards 
as elements dislocated from the duodenum. But the fact that he found 
them in the part of the stomach farthest removed from the duodenum, 
coupled with their absence from a healthy human stomach taken from an 
executed man and examined by Bensley and Revell, and with the fact 
that they have not been observed in stomachs of other mammals, not- 
withstanding the very great number which have been examined, but 
usually in a healthy condition, seems to justify the conclusion that they 
are not dislocated duodenal epithelium but are transformations of gastric 
epithelium under the influence of pathological conditions. Dean D. 
Lewis has shown me such intestinal epithelium taken from the fundus 
region of a human stomach which was affected with carcinoma. Ham- 
