December 20, 1907] 



SCIENCE 



875 



pillars; and Oordyceps, parasitic especially on 

 various subterranean insect-larvse. Attention 

 was called to the economic importance of 

 these fungi, and to the possibility of the use 

 of Empusa Anlicce, parasitic on the cater- 

 pillars of the brown-tail moth, in fighting the 

 moth-pest. The paper was illustrated by 

 specimens of the various fungi described. 



At the 91st meeting, held on November 5, 

 Dr. Caroline B. Thompson reviewed the re- 

 cent work of McClung, Montgomery, Wilson, 

 Stevens and others, on the chromosomes of 

 insects, and especially Wilson's theory of the 

 heteroehromosomes as sex determinants. 



Maey T. Hollister, 



Secretary 



THE ELISHA MITCHELL SCIENTIFIC SOCIETY 



OF THE UNIVERSITY OF NORTH 



CAROLINA 



The 173d meeting was held in the main 

 lecture hall of the Chemical Laboratory, Tues- 

 day evening, November 12, 1907, at 7:30 

 o'clock. Dr. W. C. Coker described " A Trip 

 to Porto Eico." The talk was fully illus- 

 trated with lantern slides and a large collec- 

 tion of botanical specimens. 



A. S. Wheeler, 

 - Recording Secretary 



DISCUSSWN AND CORRESPONDENCE 



lodge's ether and HUYGHENS's GRAVITATION 



The alarming density of the ether which 

 Sir Oliver Lodge believes must be taken into 

 consideration is liable to leave one more open- 

 mouthed with astonishment than did Lord 

 Kelvin's famous molasses-candy ether, even if 

 open mouths are suggested in connection with 

 the latter. But 10^' grams per cubic centi- 

 meter is not an every-day experience, con- 

 sciously at least. I have thought of it in rela- 

 tion to Huyghens's ingenious mechanism for 

 gravitation. If a body rotates in a fluid 

 lighter than itself, it must in virtue of centrif- 

 ugal force and Archimedes's principle, sink 

 toward the center of rotation. Electronists 

 insist that the ether is absolutely stationary: 

 but suppose that it rotated just a little with 

 the earth. We may then write for the buoy- 

 ancy per cubic centimeter pgoie'R and for the 



centrifugal force per cubic centimeter of sub- 

 merged matter pmWm'R, where p, o>, B denote 

 density, angular velocity and radius of curva- 

 ture, respectively. In other words 

 w Vw = = P /p =10-"; 



that is, if the angular velocity of the ether were 

 but one millionth that of the earth about the 

 sun, there would be no centrifugal force to 

 compensate gTavitation. The brilliant experi- 

 ments of our recent medallists show that ob- 

 servationally, ae^i^m- The electronist gets 

 around this by the principle of relativity. But 

 if, granting Lodge's ether as little as o),„/10' 

 would imply conditions comparable with gravi- 

 tation, one can not escape a little uneasiness 

 unless, from the interpenetration of matter 

 and ether, p„,, is ultimately, i. e., per cor- 

 puscle, much larger than p,,. As a whole, 

 however, a fixed ether would be the only satis- 

 factory inference. 



■ Carl Barus 

 Beown University, 

 Providence, R. I. 



METAGENESIS IN INSECTS 



In a recently issued paper by Professor 

 Montgomery^ attention is called again to the 

 condition approaching an alternation of gen- 

 erations in the case of insects with complete 

 metamorphosis : 



Among insects with a more or less complete 

 metamorphosis the crawling larva becomes a 

 quiescent pupa; then from a series of points of 

 the hypodermis of the pupa the organs of the 

 imago are formed, while all the remaining tissues 

 of the pupa degenerate by histolysis and then 

 become ingested by phagocytes. Therefore an 

 adult fly or moth or wasp is an individual quite 

 difl:erent from the pupa, an individual produced 

 asexually by the conjunction of a series of buds. 

 This is in every sense as truly metagenetic as the 

 development of a medusa from a polyp (Mont- 

 gomery ) . 



This is, in a way, true (the word larva, how- 

 over, should be substituted for pupa in most 

 of the above, as the histoblasts from which 

 the adult parts are derived are already dis- 

 tinguishable and have begun development in 

 the larva), and is suggestive. And the fact 



^ Trans. Texas Acad. Sci., Vol. IX., pp. 75-94. 



