PERCOLATION AND MACERATION. 
23 
ton and castor-oils, both seed-oils, and it is possible they may contain less 
gum or mucilage than olive-oil, which is from the flesh of the fruit. But of 
the general fact there can, I think, be no doubt, viz. that if an oil be packed 
while containing impurities, such as gum, mucilage, albumen, etc.., with water, 
these would be liable to putrefactive change, and would probably set up or in¬ 
crease acidification in the oil itself. My informant states, that when palm-oil 
is sent to this country dirty, it invariably contains a larger proportion of acid 
oil than that which is sent clean and fairly dry. He also adds, “ that a con¬ 
siderable part of the foots of olive-oil is not soluble in alcohol, oil, or in turpen¬ 
tine, and has no property like spermaceti or adipocere. It is undoubtedly vege¬ 
table matter of some kind, and would repay examination.” 
I remain, etc., 
King's College , June G, 1S64. C. TOMLINSON. 
THE LEECH-DESTROYER. 
TO THE EDITOR OF THE PHARMACEUTICAL JOURNAL. 
Dear Sir,—I hope to be excused for reverting to this subject. Since the pub¬ 
lication of last month’s Journal, I have received several letters from members 
and others, detailing their various experience: One gentleman suggests “the in¬ 
sect must be allied to the freshwater shrimps, of which he has hundreds in his 
leech aquarium ; and they do not attack the leeches while living.” 
I merely recommend a reperusal of the account; it is the living leech that is 
punctured,—in fact, the voracious little parasite turned from a dead leech when 
placed beside it with apparent loathing, and would not again come in con¬ 
tact. 
Another correspondent suggests that the insect is the larva of one of the 
water-beetles, probably the Nepa, known as the water-scorpion; and refers to 
Kirby and Spence as authority. 
I have an impression that some years since the Journal contained a paper 
from the French “ On the Enemies of the Leech,”* but not having all the back 
numbers bound, I am unable to ascertain if memory serves. 
I have for four months past been trying an experiment, with a view to the 
perfect conservation of leeches, hitherto with complete success, and hope in due 
course to report thereon. 
I remain, Sir, yours faithfully, 
R. Goodwin Mumbray. 
PERCOLATION AND MACERATION. 
TO THE EDITOR OF THE PHARMACEUTICAL JOURNAL. 
Sir,—I am not one of those who seem to take pleasure in finding fault with 
the British Pharmacopoeia, apparently ignoring the difficulties with which its 
compilers had to contend. I see in it much to approve, and think it a step in 
the right direction ; but having fairly tried it, the compromise between mace¬ 
ration and percolation does not, to me, appear to be a satisfactory process for 
making tincures. It has however suggested to my mind a modification of the 
old maceration process, which I have tried with satisfactory results. 
I first procured a narrow-mouthed bottle holding exactly 80 fl. oz. to the 
neck. I then weighed the ingredients for a half-gallon compound tincture of 
* Vol. xii. p. 39, “ On the Enemies of the Medicinal Leech,” by Dr. Ebrard.—E d. 
