December 23, 1904.] 



SCIENCE. 



889 



formation thus far received points strongly to 

 that conclusion. 



The skeletons of these three whales have 

 been secured for. the National Museum, and it 

 is my purpose to publish something more in 

 detail regarding them at a later date. 



F. "W. True. 

 U. S. Nation Ai Museum, 

 December 8, 1904. 



THE VASCULAR BUNDLES IN AN APPLE. 



It is probably a matter of little significance 

 or importance as to just hove many vascular 

 bundles may be found about the core of an 

 apple or how they are distributed. I have 

 seen quite a number of cuts in books and 

 bulletins, but I have never seen one that was 

 right. Any person can soon decide this matter 

 to his own satisfaction, by cutting transverse 

 sections of several varieties of apples and 

 allowing them to begin drying for a few days, 

 when the bundles may be seen sticking out 

 prominently. W. J. Beal. 



A GEOGRAPHIC DICTIONARY. 



In Science, ISTovember 11, 1904, p. 649, Mr. 

 Cleveland Abbe, Jr., states that he is com- 

 piling a dictionary of topographic terms. It 

 may, therefore, be well to draw the attention 

 of him and your other readers to a ' Glossary 

 of geographical and topographical terms and 

 of words of frequent occurrence in the com- 

 position of such terms and of place-names, 

 by Alexander Knox, B.A., F.R.G.S., * * * 

 London : Edward Stanford, 12, 13 and 14 Long 

 Acre, W. C, 1904,' price 12s 6d ($3), being 

 a supplementary volume to ' Stanford's Com- 

 pendium of Geography and Travel.' This 

 work appears richer in ordinary geographic 

 terms and components of place-names than iii 

 technical physiographic terms, and no refer- 

 ences are given to literature. 



F. A. Bather. 



SPECIAL ARTICLES. 



aster formation in enucleated egg-frag- 

 ments OF CEREBRATULUS.* 



]\fANY cytologists have accepted the view 

 that the eentriole (or centrosome) is a per- 



* Abstract of a paper read before the meeting 

 of the National Academy of Science, November 



manent and autonomous organ of the cell, 

 but the direct proof or disproof of this hy- 

 pothesis is very difficult, owing to the extreme 

 minuteness of the eentriole. The attempt to 

 obtain decisive experimental evidence was" first 

 made (1901) by E. B. Wilson by shaking un- 

 fertilized eggs to pieces and subjecting the 

 fragments to a salt solution. Asters capable 

 of division, containing centrioles, appeared in 

 a large number of the egg-fragments, inclu- 

 ding both those with and those without a 

 nucleus. It is evidently highly improbable 

 that all these centrioles can be considered as 

 the offspring of preexisting ones, since it is 

 an essential part of the centrosome hypothesis 

 that the organ is primarily single, save when 

 precociously divided into two. Wilson, there- 

 fore, came to the conclusion that some, at 

 least, of the centrioles that appeared in such 

 fragments must have been formed de novo. 

 This conclusion has since been accepted by 

 some writers, but attacked by others, partly 

 on critical grounds, partly as a result of sub- 

 sequent experiments in the same direction. 

 A source of error in the experiment undoubt- 

 edly existed in the shaking of the eggs to 

 pieces at random. Professor Wilson, there- 

 fore, suggested to me nearly two years ago to 

 perform the crucial experiments of cutting 

 the living eggs into two singly and treating 

 the fragments individually. For this purpose 

 the egg of Cerebratulus is particularly favor- 

 able, since before fertilization the first matu- 

 ration mitotic figure lies at one pole, where it 

 is seen very definitely in the living object as 

 a clear space. By cutting' off this part of the 

 egg, one may be certain that the remaining 

 portion contains no centrioles and, if centri- 

 oles appear in this portion of the egg, they 

 must have been formed de novo. 



I tried this experiment during the summers 

 of 1903 and 1904, with results which are, I 

 believe, decisive. The mode of operation was 

 as follows : all the instruments and the female 

 worm, from which the eggs were taken, were 

 first thoroughly sterilized with fresh water so 



15, 1904. In this communication the term ' een- 

 triole ' is used as equivalent to ' centrosome ' in 

 the original sense, i. e., as the dividing and fre- 

 quently persistent body at the center of the aster. 



