PKOGKESS OF MICROSCOPICAL SCIENCE. 273 



these stomata. Nor did he (the speaker) believe in the germination 

 of epithelium. With regard to endogenous cell-formation, all its 

 appearances were explained by the entrance into the cells of leuco- 

 cytes, a process which he was convinced did occui*. He had devoted 

 much time and laboiu" to enable him to recognize lymph-corpuscles, 

 and he thought he could recognize in the drawings accompanying 

 Dr. Gowers's pajier evidence in support of his view. 



Mr. Hulke said that he would receive with very much hesitation 

 the statement that leucocytes have such a remarkable tendency for 

 wandering into the tissues and into other cells. In a leucorrhoeal dis- 

 charge one found numerous large definite squamous cells, containing 

 not one, but two, three, or four definite rounded bodies, which cer- 

 tainly were not leucocytes. He instanced also the case of suppuration 

 of the vitreous humour, enclosed in its definite hyaloid membrane, 

 and separated from the choroidal capillaries by the membrana liraitans 

 and the whole thickness of the retina and the pigmentary epithelium 

 and elastic lamina of the choroid, and thought that the travelling 

 powers required by the leucocytes to penetrate all these structures 

 were more than could be granted. On the other hand, the vitreous 

 possesess traces of foetal structure, vestiges of embryonic cell-tissue, 

 which can be seen distinctly to be enlarged and replaced by bodies 

 indistinguishable from pus-cells. He was then very sceptical about 

 the enormous powers which were attributed to the white blood-cells. 



Dr. Gowers, in reply, remarked that Mr. Knowsley Thornton's 

 observations on the multiplication of nuclei in the peripheral zone of 

 vacuolated cells were interesting. He had not observed such multi- 

 plication after vacuolation, and asked whether they might not have 

 been formed before vacuolation, and pushed to the periphery by the 

 process. In reply to Dr. Thin, the character of the outer cells of the 

 nests could be seen readily, since one or two were often half detached ; 

 they were simple spindle-cells curved according to the shape of the 

 globe. He could not accept Dr. Thin's view that the second nucleus 

 within a vacuolated cell was a leucocyte which had wandered in. The 

 nucleus resembled closely the original nucleus of the. cell. If a 

 nucleus were seen in a certain position, he thought that the first 

 inference suggested was that it had been formed there, not that it had 

 wandered in. This inference was strongly supported by observation 

 of the nests of cells, since there was a simultaneous increase in the 

 number of nuclei in the centre and of spindle-cells in the outer part 

 of the nest. But the more numerous the circumferential cells, the 

 greater the obstruction to the entrance of cells from without ; and it 

 was therefore probable that simultaneous increase in the nuclei within 

 was due to their formation at the spot, and not to their migration from 

 without. 



Measurement of Nohert's Bands. — A very valuable paper on this 

 subject was some time since laid before the Royal Society, and we had 

 hoped to have had an opportunity of reproducing it in full in these 

 pages. As the opportunity has not otfered, we think it better to 

 give a portion of the essay, that relating to Nobert's bands, and to 

 give the general conclusions at which the author arrives. The paper 



