PROCEEDINGS OF SOCIETIES. 49 
scales themselves forming these markings, are consequent on the 
fact of the scales containing a particular pigment or colouring 
matter, while other members thought it might proceed solely 
from light reflected from the irregular surfaces of the scales. 
On examining lately, by transmitted light, the wings on one 
of the clear-winged moths—Sesia tipuliformis—I found on the 
transparent portion of the wing, and in addition to the markings 
on the wing, certain other scales of battledore form, and perfectly 
transparent. 
An examination with a higher power showed these scales to be 
highly striate, and, therefore, in the most proper condition for 
producing, according to the advocates of the theory I oppose, 
metallic lustre and metallic markings; and that they are in a 
condition to produce these effects, were the theory correct, is 
further shown on examination by reflected light—when, as might 
be expected from the markings, the scales are most beautifully 
opalescent, but, wanting internal pigment, give out no metallic 
markings on the wing, and a strong proof is, therefore, given in 
fayour of the theory broached by me. 
Ordinary Meeting, October 19th, 1863. 
Professor W. C. Winttamson, F.R.S., in the Chair. 
The following paper “ On Transparent Injections,” by Messrs. 
J. G. Dale, F.C.S., and Thos. Davies, was read by the Secretary. 
After enumerating the various desiderata of a transparent in- 
jecting fluid, it was observed that soluble colouring matters failed 
to fulfil them, owing to the action of endosmos, causing them 
merely to dye the tissue sought to be injected. This defect is 
shown to be remedied by the use of insoluble colouring matters in 
an exceedingly fine state of subdivision, which can only be pre- 
pared by precipitation under constant agitation, and the following 
recipe is stated to succeed admirably, showing vessels of 39/55 of 
an inch, with a clear outline even under a + objective, without 
any grain or extravasation of the colouring matter :— 
Take 180 grains best carmine, } fluid oz. ammonia, com. strength, 
SG 0-92, or 15 degrees ammonia meter, 3 to 4 oz. distilled water. 
Put into a small flask, and allow to digest without heat 24 to 36 
hours, or until the carmine is dissolved. Then take a Winchester 
quart bottle, and with a diamond mark upon it the spot to which 
16 oz. of water extend. The coloured solution must then be 
filtered into the bottle, and to this pure water must be added until 
the whole is equal to 16 0z. Next dissolve 600 grains in potash 
alum in about 10 fluid oz. of water, and add to this under constant 
boiling a solution of carbonate of sodium, until a slight permanent 
precipitate is produced. Filter and add water up to 16 fluid oz. 
Boil, and add this solution while boiling to the cold ammoniacal 
solution of carmine in the Winchester quart, and shake vigorously 
for a few minutes. A drop now placed upon white filtering paper 
VOL. IV.—NEW SER. D 
