Xettie Maria Stevens 7. 
347 
Miss Stevens’s experimental work was much less extensive. It in- 
cliided studies 011 the regeneration of hydroids and planarians. She per- 
formed the delicate Operation of separating the centrosome from the 
rest of the karyokinetic figure with the eggs of the sea-urchin. The non- 
nucleated piece, with a centrosome but without a nucleus, was foiind 
not to divide further, confirming Boveri’s conclusion that the centro- 
some alone is unable to bring about cell division. 
Miss Stevexs studied, at Professor Th. BoverTs Suggestion, the 
influence of ultra-violet rays on the development of the eggs of Ascaris. 
Miss Stevens’s work is characterized by its precision, and by a cau- 
tion that seldom ventures far from the immediate Observation. Her 
contributions are models of brevity, a brevity aniounting at times almost 
to meagerness. Empirically productive, philosophically she was careful 
to a degree that niakes her work appear at times wanting in that sort 
of inspiration that utilizes the plain fact of discovery for wider vision. 
Her single-mindedness and devotion, combined with keen powers of Ob- 
servation; her thoughtfulness and patience, united to a well-balanced 
judgement, accounts, in part, for her remarkable accomplishment. 
