170 



SCIENCE. 



[N. S. Vol. XII. No. 292. 



tion and allies of the tropical species. To 

 these greater collections we should add the 

 lesser at Copenhagen, Geneva, Vienna, Prag, 

 St. Petersburg and Madrid, all of which 

 must be visited again and again before 

 we can fully define even our INorth Ameri- 

 can tropical flora. To this end it will be in 

 order to look to the establishment of travel- 

 ing fellowships that will make possible con- 

 tinued study in those European storehouses 

 by trained American specialists. 



The time has come for American Botany 

 to assert itself in the modest way that be- 

 comes Americans, and assume its true po- 

 sition in the work of botany in the world. 

 We have the men who have profited from 

 the training of the best the Old World 

 could produce in morphological, physiolog- 

 ical, and cytological work among plants ; 

 we have young men trained and in training 

 who have the mental acumen of the best any 

 country can produce, combined with a de- 

 gree of practicality, vitality and energy of 

 which very many of the Europeans are 

 lacking ; we have men of means who are 

 philanthropic toward botanical research 

 and stand willing to aid in every work that 

 merits recognition, and if we in America 

 do not in the next quarter of a century lead 

 the world in matters botanical, it will be 

 because we are not true to the instincts 

 that guided the fathers in botany and be- 

 cause we do not enter into our heritage and 

 magnify our opportunities. 



LuciEN M. Underwood. 



COLUSIBIA UNIVEESITY. 



ARTIFICIAL PARTHENOGENESIS IN AN- 

 NELIDS {Chastopierus). 



My experiments on the ai-tificial parthe- 

 nogenesis in sea-urchins have led me to the 

 following results : (1) Through a certain 

 increase in the osmotic pressure of the sur- 

 rounding solution, the unfertilized eggs of 



some (probably all) Echinoderms can be 

 caused to develop into normal blastulse or 

 plutei. (2) This increase in osmotic pres- 

 sure can be produced by electrolytes as well 

 as by non-conductors. It is therefore prob- 

 able that the parthenogenetic development 

 is caused by the egg losing a certain amount 

 of water.* 



I considered it necessary to try whether 

 the same results can be obtained in other 

 groups of animals by the same means. I 

 have recently succeeded in producing arti- 

 ficial parthenogenesis not only in starfish 

 (Asterias), but also in worms {Clujdopterus) . 

 The experiments on the artificial partheno- 

 genesis in Annelids led to the unexpected 

 result, that the unfertilized eggs can be 

 caused to develop into apparently normal 

 larvse ( Trochophores) by two entirely differ- 

 ent methods : First, by increasing the con- 

 centration of the surrounding solution 

 (osmotic fertilization). This method is 

 qualitatively the same as the one by which 

 I produced plutei from the unfertilized eggs 

 of Echinoderms. Second, by changing the 

 constitution of the sea-water without rais- 

 ing its concentration (chemical fertiliza- 

 tion). Through a slight increase in the 

 amount of K-ions in the sea-water the eggs 

 of Chwtopterits can be caused not only to 

 throw out the polar bodies as Mead had 

 already observed, but also to reach the Tro- 

 chophore-stage and swim about as actively 

 as the larvse originating from fertilized 

 eggs. Further experiments showed that the 

 K-ions have no such specific effect upon the 

 unfertilized eggs of Echinoderms. This fact 

 may help us to understand why a hybrid- 

 ization between worms and Echinoderms is 

 impossible. I shall publish a full report of 

 these experiments in one of the next num- 

 bers of T]ie American Journal of Physiology. 

 Jacques Loeb. 



Woods Holl, July 22, 1900. 



*Loeb, J., The American Journal of Physiology, \ol. 

 IV., August, 1900. 



