322 PROCEEDINGS OF THE ACADEMY OF [May, 



together and enclosing some albumose granules. In fig. 6 it con- 

 sists, for the most part, of a homogeneous deeply staining mass 

 enclosing a few granules. For a time I regarded these masses as 

 the food, and the strands stretching toward the lumen as direct 

 eWdence that substances were being taken up by the nucleus. 

 In such cases as that shown in fig. 8, Plate XVI, which are 

 numerous with various fixations, there seemed to be good reason 

 for thinking that the substance of this mass is passing into or 

 from a granular form, under the influence of the nucleus. 

 Where, as in this cell, the nucleus lies far out in the coelomic 

 end, the mass seemed to be crowding it in that direction. A 

 number of considerations have led me to abandon this view. In 

 the fii'st place, it Avas evident from Fischer's results that the food, 

 when it enters the cell, ought to ajjpeai", according to Neumeister's 

 scheme, in the form of granules, not as a heterogeneous mass; 

 secondly, when the origin of the fine granules was traced to the 

 nucleus, another constituent of the mass was accounted for ; thirdly, 

 when the alveolar structure was made out with certainty, the 

 homogeneous constituent was seen to be interalveolar in position. 

 In such cases as fig. 6, where the alveoles are particularly distinct, 

 the strands are not to be distinguished from the fibres except by their 

 extent. Not until the injection experiments, mentioned on p. 300, 

 were tried was it possible to account for the position of the mass 

 with reference lo the nucleus. Fig. 8, Plate XVI, is from an in- 

 testine killed in the ordinary way by penetration from the coelomic 

 side ; fig. 7, A, is from one which was injected with the killing fluid. 

 Since we know that the interalveolar substance, lo which all of the 

 constituents of this mass belong, is free to move about in the cell, 

 it is clear that the position of the mass is referable to the purely 

 mechanical effects of penetration of the killing fluid. The nucleus 

 acts as an obstruction to the streaming set up by the fluid ; and in 

 some cases a kind of eddy of the interalveolar substance is formed 

 behind it. In other cases the mass projects beyond the nucleus; 

 here it is possible that the interalveolar substances have been 

 checked by reaching the limit of concentration allowed by the 

 spaces, and have been ' ' fixed ' ' in that position. Only by some 

 such supposition can I explain the remarkably straight edge pre- 

 sented by the mass on the side from which it came (figs. 6 and 8, 

 Plate XVI). Still a further evidence that the mass is wholly artifact 



