1891.] Microscopy. 183 
wonder why such an insignificant habit should be so tenacious in a 
tribe so long in contact with the whites and so much affected by their 
civilization in much more important particulars as the Passamaquoddies. 
It is conceivable that gestures like this certainly, spontaneous and in 
some respects involuntary, may furnish data of ethnological value.— 
J. WALTER Fewkes, Boston, January roth, 1891. 
MICROSCROPY.! 
Methods for the Preservation of Pelagic Organisms.—The 
publication of the methods for the preservation of marine animals em- 
ployed at the Naples Station? has called forth another contribution on 
the subject from Benedict Friedländer.’ 
Kleinenberg discovered some time since that picrosulphuric acid 
gave the best results with marine larva when it contained about 2 per 
cent. of common salt. Friedlander experimented on Hydromedusze 
and Ctenophores with regard to this point, by placing some individuals 
in x per cent chromic acid, and others, of the same species, in an 
equal volume of the same solution, to which 2-3 per cent. of salt had 
been added ; the results declared unmistakably in favor of the latter 
reagent. Still better results were obtained by fixing the specimens in 
a solution prepared by adding sea-water to a 30-40 per cent. solution 
of chromic acid until it was reduced to a 4-1 per cent. solution, the 
animals being exposed to its action for about an hour. An objection 
to the method lies in the fact that there is a danger of crystals of cal- 
cium sulphate separating out in the tissues when the specimens are 
transferred to alcohol. If the salts contained in the tissues are thor- 
oughly washed out before the transfer, there will, on the other hand, 
be a shrinkage. 
Friedlander obtained his best results by the prolonged action (5-10 
hours) of an abundant quantity of 30 per cent. alcohol, followed by 
50 per cent., 6o per cent., and 70 per cent. He concludes that a nei- 
ther too rapid nor too slow extraction of the salts contained in gela- 
tinous animals is more important for the prevention of shrinkage than 
the use of any fixatives. From many Medusæ, Salpæ, Siphonophores, 
etc., the salts can be more or less extracted before treatment with 
1 Edited by C. O. Whitman, Clark University. Worcester, 
2See AMERICAN NATURALIST for September, 1890. 
3 Biolog. Centralblatt. Bd. X., Nos. 15-16. 
Mass. 
