186 PROGKESS OF MICROSCOPICAL SCIENCE. 



size ; for the largest crystalloids are three or four times as large as the 

 largest cells, and the latter much larger than the smallest or yoimgest 

 crystalloids, so that in these respects, viz. in composition and size, they 

 cannot be confounded. Formerly Mr. Carter thought that the colour 

 of the sponges might be always sought for in the ampullaceous sacs 

 (" Wimperkorbe," Schdt.), and therefore that the black cells of Dercitiis 

 niger might be ampullaceous sacs ; * but the result of more particular 

 examination subsequently, as given above, has caused him now to 

 regard the latter more as reproductive agents. He has also alluded 

 to the presence of ampullaceous sacs in Geodia gigas, Schdt. ; but on 

 examining these also again, now that he has become more intimately 

 acquainted with the composition of the cells in Dercitus niger, &c., he is 

 led to conjectui'e that they also may be of the same kind as the latter, 

 in W'hich case, should he be right, we shall have an instance in this 

 sponge where both the globular crystalloids and the cells occm* to- 

 gether, and thence have to seek for the ampullaceous sac imder some 

 other form than that in Halichondria simulans, not only in Geodia 

 gigas, but in Pachymatisma Johnstonia and in Stelletta lactea, &c., 

 where there is nothing of the kind like the ampullaceous sac of the 

 Halichondria mentioned, so far as the larger size of its cellules and 

 peculiar grouping go. The ampullaceous sac with smaller and thus 

 less-marked cellules may exist in all ; but as yet he has not been able 

 to substantiate this. Of course, after having been dried, it is impos- 

 sible to make out anything in these cells so satisfactorily as in living 

 ones ; and hence, although such cells are present in great abundance 

 in theii" contracted state in the dried specimens of Geodia gigas men- 

 tioned (measuring about 1000th of an inch in diameter and filled with 

 a number of cellules), liquor potassaj, although it causes the cellules 

 to run together into one homogeneous mass, does not yield any satis- 

 factory demonstration of a nucleus under the addition of nitric acid, 

 nor is the cell-wall well marked — two points in which the cell of 

 Dercitus niger differs distinctly from the ampullaceous sac. 



Cancer of the Kidneys in Children. — Dr. P. M. Braidwood, who has 

 contributed an excellent article on this point to the ' Liverpool Medi- 

 cal and Surgical Eeports ' (vol. iv.), gives the following as his experience 

 of the structural degeneration seen in the gland : — The firm yellowish, 

 and the whitish less consistent portions of a cancerous kidney are 

 found to be composed of delicate fibres enclosing in their meshes 

 fusiform, round, oval, or ii-regular cells. The fibres are observed to 

 be extremely delicate, distributed sparsely, and enclosing cancer-cells, 

 which are small, oval, or round. Among the fluid contents of the 

 cysts are seen large, oval, round, or irregularly-shaped, multinuclear 

 cancer-cells. Generally at one part in the cii'cumference of such a 

 cancerous mass is to be seen a reddish edge of seemingly normal 

 tissue, which on microscopical examination is discovered to consist of 

 tubuli ui'inifcri and their malpighian terminations imdergoing can- 

 cerous degeneration. The urinary tubules at such a point appear to 

 be lined by very minute, round cancer-cells, which, on being detached, 



* ' Annals,' 1870, vol. vi., p. .332. 



