Notes. 
28 
TApril, 
Hemisphere. The name proposed for the species is Alligator 
Sinensis. 
Dr. A. Voisin finds that the brains of idiots are structurally 
little developed, remaining in a foetal condition, or at most in a 
state like that of early childhood. The convolutions are abnor- 
mally simple, and present only a few nucleoli. 
Mr. W. H. Edwards, in the “ Canadian Entomologist,” re- 
cords the singular fadt that ants cherish the caterpillar of Lyccena 
pseudargiolus (a small butterfly closely resembling the “ blues ” 
of English collectors), for the sake of a clear, green fluid, doubt- 
less of a saccharine nature, which exudes from a peculiar mamil- 
loid organ on the back of the eleventh segment, The most 
perfect understanding seems to prevail between the ants and the 
caterpillars, which must thus rank with the Aphides among the 
domestic cattle kept by our six-footed rivals. 
Chemistry and Technology. 
In a note on large crystal growing Mr. C. W. Quin remarks 
that a great difficulty is to guard against sudden rises in tem- 
perature, which generally have the effeCt of causing the growing 
crystal to be partially and unevenly re-dissolved. To receive a 
continually even temperature, after many experiments he hit 
upon the plan of plunging the beaker containing the growing 
crystal into the house-cistern, the temperature of the water in 
which never differed by more than 0-5° F. either way day or 
night. To prevent the solution from becoming exhausted too 
rapidly he immersed in it to the depth of half an inch or so a 
crystal drainer containing a filter-paper full of the salt to be 
crystallised, so that a constant stream of strong solution was 
continually descending on the growing crystal. 
The double staining of vegetable tissues, various processes for 
which have been noted under “ Microscopy ” from time to time 
in the “Journal of Science,” has proved eminently successful in 
rendering structural details more evident. Those portions con- 
sisting of tissues hardened by much secondary deposit absorb 
the dye with avidity, and in the washing process part with it but 
slowly, so that the simpler tissues are deprived entirely of their 
colour before the hard parts yield up theirs ; careful staining with 
another dye follows, and the effects of differential colouring are 
very apparent. Some operators have used three and four colours 
with great success. 
M. G. de Plessis* recommends bichromate of potash for the 
preservation of delicate marine organisms, such as polypes, 
Medusce, Salpce , &c. The solution can be made in either fresh 
or salt water, and a weak solution answers well, exaCt proportions 
* Bulletin de la Societe Vaudoise des Sciences Naturelles, ser 2, vol. xv., 
pp. 278—280, April, 1878. 
