382 



SCIENCE 



[N. S. Vol. XLIX. No. 1268 



Eieracium on the other. The doubling of 

 chromosomes, the terminology of partheno- 

 genesis, the nucellar embryos, the lessened 

 fertility and many other effects of hybridizing, 

 as well as those of vegetative propagation are 

 extensively dealt with. From this survey the 

 author concludes that Chara crinita seems to 

 afford the best material for further studies 

 and gives an ample review of the mode of 

 propagation of this algae. 



It is a dioecious plant, which has a par- 

 thenogenetic variety. The latter has been 

 described by Alexander Braun as early as 

 1856 and since by numerous authors. The 

 species is rather rare; in some stations it is 

 found without the variety but in the larger 

 nmnber of localities only the apogamous form 

 occurs. In some, however, both grow together, 

 indicating the possibility of a repeated origin 

 of the variety from the dioecious type. More- 

 over it is shown that the differences between 

 the two types are of such a kind, that they 

 can not have originated slowly and gradually 

 but must be assumed to be due to a sudden 

 change (p. 104). This is the well-known way 

 in which in other cases mutations are seen 

 to arise. The probable difSeulties of the in- 

 tended investigation are then amply discussed. 

 To these the reviewer might add the objection 

 that it is a species which has already produced 

 an apogamous form, and probably more than 

 once and which therefore may be expected to 

 repeat the mutation from time to time, even 

 without the aid of experimental .interference. 

 Furthermore, the experience with the evening 

 primrose has shown that mutations occur in 

 crossed progeny as well as in pure lines and 

 the research of Baur on Antirhinum and of 

 Morgan on Drosophila have amply confirmed 

 this result. Among hybrid progenies they 

 seem to be more numerous, but only in con- 

 sequence of the fact that such cultures usually 

 embrace many thousands of individuals more 

 than are kept in the pure stocks. The same 

 will be the case in the cTiltures of chara crinita 

 and the expected occurrence of apogamous 

 mutations in hybrid families can, therefore, 

 not be regarded as a proof of their origin by 

 means of hybridization. 



But it seems highly desirable that the ex- 

 perimental trials should be made, the more 

 while in any case the gain for the theory of 

 mutation must be expected to be of the high- 

 est importance. 



Hugo de Vries 



LuNTEREN, Holland 



PRELIMINARY REPORT OF EXPERI- 

 MENTS ON THE ACTION OF DI- 

 CHLOROETHYLSULFIDE 

 (MUSTARD GAS) ON 

 THE CELLS OF 

 MARINE OR- 

 GANISMSi 

 The toxic action of a sample of " mustard 

 gas " sent us by Major H. C. Bradley, of the 

 Chemical Warfare Service, has been investi- 

 gated on a number of typical marine organ- 

 isms, including various swimming larvse (sea- 

 urchin, starfish, squid, the annelids Nereis 

 and Arenicola), the developing eggs of sea- 

 urchin and star-fish, the spermatozoa of sea- 

 urchin and starfish, and young and adult fish 

 (Fundulus). The most satisfactory objects for 

 experimentation have proved to be the develop- 

 ing eggs of the starfish (Aster^s forhesii). 

 and most of our work has been carried out 

 with this material. Changes in the rate and 

 character of cleavage in the eggs after treat- 

 ment with " mustard," the production of ab- 

 normalities of form and structure in the larvse, 

 and the degree of ciliary activity, furnish a 

 very delicate index of toxic action. Valuable 

 information has also been obtained with Aren- 

 icola larvse and with small fish (Fundulus) . 



In the experiments with fertilized starfish 

 eggs we have investigated the influence of 

 solutions of the " mustard gas " in sea-water 

 upon the cleavage and early development (up 

 to the gastrula stage). The procedure chiefly 

 employed was as follows: A small quantity of 

 the " mustard gas " (ca. 5 grams) was shaken 

 vigorously with one liter of sea-water in a 



J This preliminary report in its present form 

 was sent to the Medical Section, Chemical Warfare 

 Service, September, 1918. A more detailed ac- 

 count of these experiments will be published in 

 the near future. 



