PBOGRESS OF MICROSCOPICAL SCIENCE. 235 



into glassy, clear, rounded masses ; but lie lias never noticed the free 

 formation of cells in a blastema, and does not believe that the white 

 corpuscles of the blood or " migrating cells " play any jDart in the 

 regeneration of the cells, though he has occasionally met with them 

 between the ej^ithelial cells and in the substance of the cornea in the 

 vicinity of the injury. In no single instance has he observed any 

 appearance leading him to think that they undergo conversion into 

 epithelial cells. The j^rocesses thrust forth by the cells, as above 

 mentioned, were found, from observations extending over many hours, 

 during which the cornea was placed in a current of serum, to undergo 

 slow changes of form and size, the movements however being in no 

 W'ay comparable in activity to those of amoeboid cells. The cells situ- 

 ated at a greater distance from the injured part often became gi'anular, 

 and their margins more distinct. In rats both the ujiper flattened and 

 the deeper, more coliunnar cells seemed alike to thrust forth the pro- 

 cesses destined to cover the floor of the injured part. Dr. Heiberg 

 expressly remarks that he has not satisfactorily followed the sej)aration 

 of the cell-processes to form new cells, which again push oiit new out- 

 growths, to be again detached, though he obviously thinks this is what 

 really occurs. Dr. Heiberg gives several drawings to illustrate the 

 points mentioned in his paper, which is in every respect a most valu- 

 able contribution. 



The Microscopic Structure of Cotton-seeds. — This is a paper, pub- 

 lished in the ' Neues Jahrbuch fvir Pharmacie,'* by Dr. F. Fliickiger. 

 It is a long paper, and contains, in the first place, a succinctly-written 

 botanical description of the several kinds of shrubs and trees from 

 which cotton is obtained ; next, we meet with a histological and 

 morphological minute description of the microscopical structure of the 

 cotton-seeds, illustrated by coloiu-ed lithographs. The latter portion 

 of this essay is devoted to a well-condensed and very complete review 

 of all that has been done in various parts of the world in reference to 

 the scientific, as well as industrial, researches on cotton-seeds, and the 

 oil it yields. According to the author, the quantity of cotton-seed 

 annually gathered amounts to 1,000,000,000 of kilos., which, under the 

 least favoui'able conditions, would yield 150,000,000 kilos, of oil. 



Discovery of the Animal of the Spongiadce confirmed, — Mr. H. J. 

 Carter, F.K.S., sends a line to ' Silliman's American Jom-nal ' (July), 

 "just to tell you what you will be glad to learn, viz. that I have con- 

 firmed all that Professor James Clark, of Boston, has stated about 

 the sponge-cell, and much more too. It is after all only what was 

 published and illustrated in the ' Annals ' in 1857. Indeed I am 

 astonished now at the accuracy and detail of that paper,f now cdl con- 

 firmed by an examination of a marine calcareous sponge. I have not 

 only fed the sponge with, indigo, and examined all at the moment, 

 but the sponge so fed w-as put into spii'it directly afterward, and noio 

 shows aU the cells (monociliated) with the ciliu>n attached and the 

 indigo still in the cells. This, I think, will break down Hackel's 

 hypothesis, which is as imaginative and incorrect as it is beautiful. 

 His " Magosphfera " too is figured in the ' Annals ' (1856), and de- 



* Double number, May an J June, 1871. 

 t " Ultimate Structure of Spongilla," &c. 



