932 
Science, the botanical department of the Univer- 
sity of Pennsylvania, and the various field club- 
are fully exploited, the pages being interspersed 
with numerous half-tone illustrations of points 
of botanical interest, in addition to many excel- 
lent portraits, the full-page illustrations amount- 
ng to forty-eight. The work is written in a 
pleasing style, is well printed, and forms an 
attractive volume. The portions relating to the 
earlier botanical workers who gave to Philadel- 
phia its early botanical prestige are particularly 
interesting. Additional matter of general in- 
terest is found in the historical account of the 
scientific journals and serial publications that 
have been issued from Philadelphia. An inter- 
esting account of the historic trees of the 
vicinity closes the work. 
The author is sanguine that Philadelphia ‘is 
peculiarly fitted to be the botanical center of 
America,’ and his references to ‘the metropoli- 
tan lifeand publishing houses’ of New York on 
the one side, and ‘the libraries and scientific de- 
partments’ of Washington on the other, illus- 
trate well how near one can live to cities and 
yet fail to appreciate their most salient features. 
Lucren M. UNDERWOOD. 
The Maturation, Fertilization and Early Develop- 
ment of the Planarians. By WILLARD G. VAN 
Name. From Trans. Conn. Acad., Vol. X., 
p. 263-300, pl. xxxvi.—xli. August, 1899. 
The author has studied the early life history 
of Eustylochus ellipticus (Girard), and Planocera 
nebulosa Verrill with great care. The charac- 
teristic features of each structure are presented, 
so far as could be determined from the study of 
the material, which is not favorable for the 
solution of certain points. While the results 
obtained agree in the main with those of pre- 
vious observers, light is thrown on a number of 
doubtful points. Especial mention may be 
made of the discussion of the centrosphere and 
its parts, as well as that on the interesting 
modifications in the form of the chromosomes. 
The paper is well illustrated. H. B. W. 
SOCIETIES AND ACADEMIES. 
BIOLOGICAL SOCIETY OF WASHINGTON. 
THE 313th meeting of the Society was held 
Saturday, December 2d. W. H. Dall exhibited 
SCIENCE. 
[N.S. Von. X. No. 260. 
a specimen of the fruit of a species of Barring- 
tonia stating that it was used for capturing 
fish, the kernel being bruised and cast into 
small ponds or streams whereupon the fish be- 
came stupetied and rose to the surface, where 
those that were wanted were gathered. The 
effect upon the fish was only temporary, those 
not taken soon recovering. 
Frederick V. Coville showed an entire and a 
bisected cone of Pinus alternata both covered 
with lichens. Mr. Coville stated that these 
cones remained on the trees from 20 to 50 years 
and seemed to open and release the seeds only 
when exposed to great heat, so that no seed- 
lings of this pine were to be seen except where 
the ground had been swept over by fire. 
L. H. Dewey spoke on ‘ Frost Flowers,’ say- 
ing that this name is applied to peculiar for- 
mations of ice found on certain plants on frosty 
mornings in fall and early winter. They are 
most frequently observed on dittany, Cunila ori- 
ganoides ; frostweed, Helianthemum canadense ; 
marsh fleabanes, Pluchea camphorata and P. 
fetida, and on the Pacific coast on the culti- 
vated heliotrope. The first published record 
of the phenomenon appears to be that of Dr. 
Stephen Elliott, in 1824, who observed it on 
Pluchea fetida (‘Conyza bifrons’) and made a 
note of it in his ‘Botany of South Carolina avd 
Georgia.’ It has since been observed, studied 
and written about by many botanists and phy- 
sicists. It is apparently purely physical in 
character, due to capillary movemeut of water 
aud the action of frost, but no thoroughly satis- 
factory explanation has yet been given why it 
should be found on only about twenty-six species 
of plants and not on others. Further observa- 
tions in the field at this season are needed to 
determine whether frost flowers may be found 
on species other than those recorded, and also 
further studies are needed on the structure of 
plants exhibiting the phenomenon. 
H. J. Webber presented a paper ‘The Effect 
of Hybridization in the Origination of Cultivated 
Plants,’ calling attention to the remarkable de- 
velopment of certain of our cultivated plants, 
due to the effect of hybridization. It was 
pointed out that this is particularly true in the 
grape where 57 per cent. of the sorts of known 
parentage are hybrids while only 29 per cent. 
