1902.] NATURAL SCIENCES OF PHILADELPHIA. 329 



From twelve hours after feeding onward, just as in the proteid 

 absorption, the food is usually aggregated mainly on the coelomic 

 side of the cell (figs. 17, 16 hrs. ; 19, 115 hrs. ), although as in figs. 

 18 (50 hrs.) and 10, Plate XVI, (24 hrs.) it matj be still widely 





Fig. 17.— Section of cell X 600 from median portion, "mid-gut" of 

 PorcelUo scaier, fed with butter ; ibtestine fixed after 16 hrs. as in fig. 

 15. All black granules outside the nucleus are fat. Nucl., nucleolus : 

 the chromatin is precipitated in short radiating strands immediately about 

 its periphery. 



scattered through the cell at a much later period. The difference 

 here is due in part to the different kinds of fat used — butter in figs. 

 15, 16 and 17, beef suet in 19 and olive oil in 10, Plate XVI — and 

 in part to the difference in form of the cells in anterior (15), in- 

 termediate (16) and median (18) portions of the " mid-gut."^' 



Just as in the absorption of proleids, the passage of food through 

 the median cell is facilitated by the relatively easy exit from the cell 

 into the coelome, while from the anterior cells the passage is hin- 

 dered by the investing muscle layer. Consequently at any given 

 time after the digested product has reached all the cells, the median 



1" The position of the fat in the cell is not affected by the direction of 

 penetration of the killing fluid, as nmy be seen from the fact tliat fig. 18 

 is from an intestine injected from the posterior end with Hermann's 

 fluid. There has been no movement of the fat on account of penetration 

 from witliin. 



