90 PRESERVATION OF MEDUS#. 
structure of the central peduncle. Conveying our prizes then to a dark place, we irritate 
them, and observe whether they phosphoresce or not, of what colour the light is, and how 
long it endures. 
In every case a drawing, as careful and detailed as possible, and always coloured, should 
be made at the time. This is the more necessary, since they are animals extremely difficult 
to preserve, shrivelling up into indistinguishable curd-like masses in spirits, and most 
preserving fluids. In fact, the only specimens which I have seen preserved in a distinguishable 
state, have been so by means of one of Mr. Goadby’s fluids. When Mr. Goadby accompanied 
Mr. M‘Andrew, in 1837, on a cruise among the Hebrides and Zetlands, he made many 
experiments on the preservation of these delicate creatures, and succeeded so well that I have 
been able to distinguish among them even the several species of the critical genus 7haumantias. 
I do not despair of seeing, before very long, a series of these creatures so preserved exhibited 
in the British Museum, and contributing to render more perfect the finest natural-history 
collection in the world. The indefatigable director of the zoological department in that truly 
national establishment, will yet, I trust, sanction such an addition, and, as he no longer 
remains a sceptic in bones or disbeliever in spirits, may consistently extend his faith to 
Goadby’s fluid. 
Nore.—KInpdLY COMMUNICATED BY Mr. Goapby. 
To preserve the Acalephe.—These animals contain so large a quantity of water, that they 
require great care and attention to preserve them. 
The B fluid of itself is not enongh for the purpose, the assistance of alum being imperatively 
necessary to give firmness and support to the several tissues. 
The plan that I adopted with great success was the following: 1. e. 
Make a saturated solution of bay salt, and when cold, test it with a specific-gravity bubble 
prepared for that purpose. 
When required for use, dilute it (with water) to 1148, indicated by another bubble so marked. 
To this latter fluid add alum, at the rate of 3ij to every quart of fluid, and dilute the whole to 5 strength 
with water. Pour this into a dish, and empty the contents of the tow-net (containing the well-drained 
specimens of Acalephz) into it, and let them macerate therein for twenty-four hours, by which time 
they will be found saturated with the fluid, and at the bottom of the dish. If the specimens be small, 
they should now be moved, and placed in fluid consisting of dissolved bay salt, only to the strength of 
1148, as the alum destroys transparency. 
Large specimens of the Acalephe, as Aurelia, &c., offer exceptions to this rule; they may be 
allowed to remain in aluminous fluid (to be changed daily) of the strength described, or somewhat 
increased by additions of stronger saline finid, for a longer period (two or three weeks), but ultimately 
they, too, must be removed from the continued influence of alum, and kept in the bay salt fluid, of not 
less strength than before described, viz. 1148. 
The fluid should be tested with the bubble daily, and its strength made up by additions of the 
saturated solution, until it obey the test for several consecutive days, when endosmose and exosmose being 
at an end, the process of preservation may be considered complete. 
For permanent preservation, corrosive sublimate should be added to the preserving fluid, in the 
proportion of grains ij per quart of fluid, but its use is unnecessary in the early stages of preservation. 
I did not employ it until the collection of last summer was complete, and on shore. Neither is it 
essential to filter the fluid if time be pressing: at sea, of course, it cannot be done. Finally, marine 
animals require for their preservation saline fluid of the specific gravity of 1148. Fresh water and 
terrestrial animals are preserved at the diminished strength of 1100; fluids of less strength (respectively) 
are insufficient, and greater strength is injurious. 
