ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
671 
hatched larvae, entering in the note-book the time required for hatching. 
Meanwhile, if it is desired, and this is the better plan, the moth is 
mounted after the usual manner of entomologists, on an entomological 
pin, and preserved in a cabinet with the same reference letter, so that 
the species can be determined at leisure. The carbolic acid renders the 
eggs perfectly transparent, or at least does so in the cases which have 
come under notice, and hence the embryos can be observed in the various 
stages of development. Mr. Hill mounts in benzol-balsam direct from 
the carbolic acid, and to prevent the crushing of the eggs sometimes 
uses three supports for the cover-glass placed triangularly between it 
and the slide. Three are better than four, as three points afford a more 
uniform bearing for the cover than four, on the well-known principle of 
the three-legged stool. 
For the supports either small beads are used, or, if special thick- 
nesses are required for the supports, they can be made by drawing out 
a fine thread from a piece of glass tube by means of a spirit-lamp, after 
which small pieces can readily be broken off. Tin-foil also makes good 
supports. For example, cut a strip about 1 in. square, and roll it into 
a tight roll 1 in. long ; it should then be flattened between two glass 
slides to a uniform thickness, when little square pieces can be readily 
clipped off with a pair of scissors and used instead of the beads. The 
thickness of the roll can be varied, and the little squares can also be 
reduced in thickness by removing one or more layers of the tin-foil until 
of the proper size. 
Theoretically, a series of eggs beginning with No. 1 and running up 
consecutively should show a progressive development of the embryo, 
but practically there is not always as much regularity in the series 
as we could look for. Probably the eggs first laid develope first, and 
twelve hours’ difference in the time of laying the first and last egg, if 
the whole period of incubation only amounts to a few days, may make 
some difference. When, however, we have several eggs in each phial, 
no trouble will usually be experienced in getting a good progressive 
series by making a judicious selection from each bottle, in which case 
the selected specimens may be mounted in proper order on a single 
slide. 
Preparation of Eyes of Lobsters.* — Mr. Gr. H. Parker describes a 
method of staining nerve-fibres which he discovered while experimenting 
with Weigert’s hsematoxylin. The method consists in a cautious use of 
Schallibaum’s fixative ; the one employed consisted of three parts of oil 
of cloves, and one part of Squibb’s flexible collodion ; the mixture should 
be allowed to stand a week before being used. A moderate amount is 
applied to the slide, and the sections in paraffin are placed on it ; the 
slide and the sections are now subjected to a temperature of 58° C. for 
fifteen minutes, and this is a point which must be carefully attended to. 
The slide must next, while warm, be thoroughly washed with flowing 
turpentine, which can be conveniently applied from a small wash- 
bottle; all the paraffin should be removed from the slide before it 
becomes cool. When the slide is cool the turpentine may safely be 
replaced by alcohol, 95 per cent., then 70 per cent, 50 per cent., and 
* Bull. Mus. Comp. Zool., xx. (1890) pp. 3-1. 
