772 



SCIENCE 



[N. S. Vol. XXXIV. No. 883 



the latter, excellent results were obtained* as 

 far as the living of the cells is concerned, but 

 the unfortunate condition arose invariably 

 that a large spirochaste Spirochwte halhanii, 

 perhaps, grew in such numbers that the cells 

 were soon covered with their growths and dis- 

 integration ensued. All attempts at freeing 

 the medium from this animal, such as the use 

 of HgCL in various dilutions with the ces- 

 tode before the tissue was teased were of no 

 avail and the experiments in this direction 

 were abandoned. 



Difficulty was experienced in regard to the 

 invasion of bacteria and spirochsetes into the 

 plasma mounts, but their growth for some 

 reason was not as pronounced as with sea- 

 water and indeed in many cases, no bacteria 

 or spirochetes were found after ten days 

 time. Therefore the plasma method was 

 used throughout the experiments. 



It was expected that the cells, which could 

 be made to live in apparently good condition 

 for several weeks in the plasma medium would 

 undergo the process of fission and during the 

 earlier stages of the study, I was convinced 

 that I was observing such a phenomenon, but 

 I finally was driven to the conclusion that 

 what I saw was in no ease cell division, but 

 rather an association of the cells in twos 

 which resembled a cell undergoing reproduc- 

 tion. I am under the impression that the 

 cells which are cultured in this way do not 

 undergo cell-division at all. I made charts of 

 the slides which I had under observation for 

 a week at a time and checked the behavior of 

 all of the cells in each slide with camera 

 lucida drawings, comparing those made one 

 day with those made on the day previous. K 

 any increase in number of the cells had oc- 

 curred, I should have noticed it, of course. 



In order that the cells may be stained for 

 nuclear contents, it was necessary to take 

 down the preparation and float the cover upon 

 a saline sokition for an hour so that the fibrin 

 should dialyze out and I am under obligation 

 to Professor Harrison for this technique, 

 which is quite necessary, for otherwise the 



* Compare Lewis and Lewis, 1911, Anatomical 

 Mecord, 5: 277. 



fibrin takes the nuclear stain to such a degree 

 that the cells of the cestode become indis- 

 tinguishable. Heidenhain's iron-hematoxlin, 

 bismarck brown (used as an intra-vitam 

 stain, as well as for fixed preparations), Ehr- 

 lich's hematoxylin, safranin and other stains 

 were used, but all of them gave consistent re- 

 sults to show that cell-division was not taking 

 place. The preparations were in some cases 

 dried in the air or over a flame and mounted 

 directly after staining. In other cases, the 

 covers were inverted over osmic fumes and 

 then passed through the alcohols into balsam. 



Typical resting nuclei were seen in all of 

 the preparations, but no indication of cell- 

 division could be determined. It may be that 

 cell-division occurs in rhythms as indeed is 

 the case in Crossohothrium according to the 

 results of W. C. Curtis and it may be that 

 the period over which these present experi- 

 ments extended did not cover the fission 

 period. They were begun July 5 and extended 

 to August 15. 



In regard to the matter of regions in the 

 cestode where fission is more likely to occur, 

 such as the region immediately posterior to 

 the scolex, in the " growth regions " of 

 Crossobothrium, described by Curtis and in 

 the maturing sex products, it may be said 

 that all of these regions were examined by 

 the methods described in this communication. 

 No difference could be determined between 

 the cells from one region and those from 

 another. 



While the results were unsatisfactory as 

 far as the end desired is concerned and while 

 they are negative throughout, it seems to me 

 that the method may be applied to more favor- 

 able material where the character of cell-di- 

 vision is in question. The unmistakable pres- 

 ence of mitosis in the sarcoma tissue investi- 

 gated by Lambert and Hanes, where amitosis 

 has been so frequently described, is an in- 

 stance in point. The " amitosis " of the fol- 

 licle cells of insects is desirable and ever 

 available material for such an investigation. 



TRINITY COLLEGE, M. W. MOKSE 



Hartfoed, Conn., 

 November 1, 1911 



