324 
crease, which can be eventually checked, shows 
that active commercial killing should have 
been restored some years ago. 
The destruction of tetanus antitoxin by 
chemical agents: W. N. Bera and R. A. 
Keser, Pathological Division, Bureau of Ani- 
mal Industry, Washington. The results in- 
dicate that tetanus antitoxin a substance of 
non-protein nature, but the stability of the 
antitoxin is so dependent upon that of the 
protein to which it is attached, that whenever 
the protein molecule is split, the antitoxin 
splits with it. 
Tests for fluorine and tin in meteorites with 
notes on maskelynite and the effect of dry 
heat on meteoric stones: GrorcE P. Mrrrmu, 
Department of Geology, United States Na- 
‘tional Museum, Washington. 
Notes on isotopic lead: FRANK WIGGLES- 
WORTH CLARKE, United States Geological Sur- 
vey, Washington. Investigations on the atomic 
weight of various forms of lead, and radio- 
active estimates of the age of minerals, are 
analysed for the purpose of throwing light 
upon isotopes and the structure of chemical 
elements. 
THE seventh number of Volume 4 contains 
the following articles: 
On the representation of a number as the 
sum of any number of squares, and in par- 
ticular of five or seven: G. H. Harpy, Trinity 
College, Cambridge, England. 
The crystal structure of ice: Ancrt Sr. 
JouHN, Department of Physics, Lake Forest 
College. Ice is properly assigned to the hex- 
agonal system, and consists of four inter- 
penetrating triangular lattices, of which the 
fundamental spacings have been obtained. 
Fringing reefs of the Philippine Islands: 
W. M. Davis, Department of Geology and 
Geography, Harvard University. An inter- 
pretation of recently published large-scale 
charts of the United States Coast and Geo- 
detic Survey. 
Dilation of the great arteries distal to 
partially occluding bands: Wiuram S. Hat- 
sTEAD, Medical School, Johns Hopkins Uni- 
SCIENCE 
[N. 8. Vou. XLVIII. No. 1239 
versity. The relative amount of constriction 
required to give the most pronounced results 
has been determined, so that the author is able, 
in almost every instance, to produce the 
dilation, and a large amount of material 
thereby accumulated is analyzed. 
On the correction of optical surfaces: A. A. 
MicueExson, Ryerson Physical Laboratory, Uni- 
versity of Chicago. 
Epwin Bmwett Witson 
Mass. INSTITUTE oF TECHNOLOGY, 
CAMBRIDGE, MAss. 
SPECIAL ARTICLES 
INVESTIGATIONS ON THE IMBIBITION OF 
WATER BY GELATINE 
Many investigators in both botany and 
zoology have recently been at work on the 
absorption of water by gelatine and other 
colloidal jellies and from their results have 
drawn some extremely interesting conclusions 
regarding physiological behavior. However as 
the published results accumulate many ap- 
parent discrepancies in actual experimental 
results are appearing. In an attempt to in- 
vestigate some phases of imbibition by gel- 
atine, I found difficulty in making my con- 
clusions agree with those of previous workers 
and even in duplicating my own results. In 
the course of this work certain phenomena of 
the behavior of gelatine itself came to light 
and I am offering the following account of 
some of the preliminary work which I found 
necessary, in the hope that it may save other 
workers needless trouble and perhaps help to 
clear up some of the discrepancies referred to. 
Various authors have emphasized the ne- 
cessity for using material of a constant chem- 
ical composition, and for conducting all com- 
parable tests at the same temperature, but the 
importance of an identical history of water- 
content and of water-loss seems to have been 
overlooked. 
As was to be expected, the water-content of 
the gelatine at the beginning of the absorp- 
tion, strongly influences the rate of water up- 
take. However, even when different lots of 
gelatine have the same water-content at the 
beginning of the absorption, their ability to 
