(1) A correspondent in 'Mem. de Med. et de Pharm. Milit.' says, after various experiments and the test of 8 months' exposure to the sun and heat of summer, he has come to the following conclusion: - Heating the juice, or adding alcohol to the same, would appear to be superfluous, as it is only necessary to filter it and keep it in sealed bottles; however, since filtration proceeds so very slowly, the best way is, perhaps, to add 10 per cent, of alcohol to the fresh juice, and bottle.
(2) The ' Pharm. Jl.' observes that it may be preserved, without the addition of alcohol, by heating it to 150° F. (65 1/2° C), and then excluding it from the air by carefully closing the full bottles at this temperature. The operation should be carried out in winter.
Raulin's andPasteur's Fluids.
- Both Pasteur's and Raulin's fluids are very difficult to keep. They are so extremely sensitive that the simple exposure of the fluids to air for 2 or 3 days (in a town) is sufficient to convert the whole into a ropy mass of mycelium. Then, again, starch solution is not easy to keep for any length of time. Chemists have, it is true, succeeded somewhat by the application of salt, calcium chloride, and other antiseptics; but these more or less interfere with the universal application of starch solution, and could not be used at all with either Pasteur's or Raulin's fluid. Two years ago, G. E. Davis devised a plan for keeping such fluids as are above-mentioned, and with the result that the remainder of a pint of Raulin's fluid made up in November, 1878, was as good 4 years after as when first mixed. The apparatus consists of an ordinary glass flask, fitted with an indiarubber stopper pierced with 2 holes, into one of which is tightly inserted a tube packed with clean cotton wool. Into the other hole the shorter limb of a glass siphon is inserted, the longer limb being closed with a spring clip upon a short length of rubber-tubing, in advance of which is a narrow glass jet.
To put the apparatus in working order, nearly fill the flask with the fluid, and take out the cotton wool from the tube above; place over a lamp to boil, and, while boiling, open the clip, and stop up the open end of the wool tube, so that the pressure may drive some of the fluid out of the flask. Return this ejected fluid to the flask, and keep boiling for 5 minutes, allowing the steam to escape from the open wool tube. While steam is thus escaping, place a plug about } in. in depth of cotton wool, and allow the steam to blow well through it. After 1 minute, plug the whole of the tube with cotton wool, and withdraw the flame. By simply opening the clip, a supply may now be withdrawn without the introduction of any atmospheric germs into the flask. (Northern Microscopist.)