500 Edwin G. Kirk. 
At 15 em., many of the surface cells have gobletsreaching clear 
to the nucleus, while some show merely a superficial rim, there 
being no regularity in the distribution of these types. 
At 18 em., the mucous chief cells line the lower third or 
quarter of the tubule, the goblets the upper 3 or #, the deeper in 
position having, as hitherto, the shallower goblets. At 26 em., all 
the surface and foveolar cells have very deep goblets. 
Thus cyto-differentiation in the pylorus is practically com- 
plete at 9em. The size of the cells, the depth of the goblets and 
other details alter somewhat later, but, microchemically and pre- 
sumably, metabolically, the cells have then reached their definitive 
condition. I do not mean to imply that they have reached a ter- 
minus of potential differentiation. Harvey’s work (’07) shows 
that very probably even the adult gastric cells, highly specialized 
as we are accustomed to consider them, may under changed condi- 
tions, pathologic or experimental, assume other forms and func- 
tions. But this seems not to occur in normal, embryological 
cyto-differentiation in the pylorus. 
Measurements were taken of glands from each region at all 
stages but inasmuch as such figures have no general embryo- 
logical value, I quote only afew, and these for the purpose of com- 
paring the rapidity of growth in these regions. Such figures are 
necessarily only approximate, as there are considerable differences 
between those from embryos of the same length, and also between 
adjacent tubules. 
Sem. 16cm. 19cm 23cm. 29cm. 
Cardiac ies sete oat 35-50u 80u 105u 112u 160. 
EIN CUS er eee 70u 110u 140u 165u 210u 
Pvlorasteneciocetcor tees 80-110u 130u 160u 208u 240u 
3. Fundus 
From the first we have found considerable difference between 
cardiac and fundic tubules, but the two districts have always 
merged insensibly and the distinctions have been those of size and 
age, depending on the general precocity of the right and retarda- 
a 
