350 Mr Corry, On some points in the structure and [Ap. 30, 



aniline colours just mentioned, yet these same strands on treatment 

 with Methylene Blue or the Chlor. Zinc. Iod. method stain in the 

 manner characteristic of undoubted cellulose Avails. So far there 

 is not the slightest appearance of any infolding or intrusive 

 ingrowth of the cell wall having taken place, for its outline remains 

 perfectly straight, uniform, and is very little thickened if at all. 

 Those filaments which have not become chemically altered remain 

 in their protoplasmic condition stretching from the nucleus to the 

 primordial utricle lining the cell- wall. When an older stage is 

 examined each cell may be observed to have increased in size over 

 the entire periphery, with the exception of the points of insertion 

 of the cellulose or protoplasmic filaments which firmly attach it to 

 the nucleus: at these places it is held in and prevented from doing 

 so. The cell- wall is moreover observed to have become thicker. As 

 a consequence of this tension at certain points the outline of the 

 cell becomes irregular and presents depressions or bays along its 

 walls. The cell still continues to increase in size while the points 

 before mentioned are still held in, and soon slight apparent 

 infoldings or involutions (of the cellulose wall, the double nature 

 of which is obvious), proceeding towards the interior become ob- 

 servable in the cell cavity as shallow depressions which become 

 elongated and tubular, and give the cell a very peculiar and 

 characteristic aspect. The two limbs or halves of each of these 

 infoldings rapidly come to be very closely approximated, except 

 sometimes at their outer and inner ends, and form apparently a 

 single ingrowth which is slightly thickened and pyriform in shape. 

 The space between the two limbs is now merely a line, while the 

 extremity which projects into the lumen is thickened and fillet- 

 shaped. The enlargement of the cell goes on, and the result is 

 that many of the protoplasmic filaments break away from their 

 attachment to the apparent infoldings of the wall and are probably 

 withdrawn into the immediate neighbourhood of the nucleus. The 

 majority of the apparent infoldings or ingrowths 1 therefore remain 

 small and abortive, but one or several remain to which the nucleus 

 is attached either by protoplasm or by the intermediation of a 

 strand or strands of cellulose (formed by conversion of the pre- 

 existing protoplasmic strands as already described), or else directly. 

 The nucleus in many cases exhibits a tendency to become 

 attached directly to one of the infoldings of one wall, this is due 

 to the filament of protoplasm which connected it being shortened 

 and the pseudo-infolding being in this way drawn towards it until 

 the two meet: the nucleus still however retains its connection by 

 cellulose or protoplasmic filaments with other walls. In some cases 

 a band of cellulose is formed by conversion of the protoplasm round 



1 They all give the characteristic cellulose reactions with Methylene Blue and 

 the Chlor. Zinc Iod, method. 



