CAUSE OF CHANGE IN ESSENTIAL OILS. 
637 
In order more fully to investigate the matter, the remaining leeches were 
transferred to a large glass jar. The first noticeable circumstance was their ex¬ 
treme restlessness—at first attributed to the strong light—but on closer inspec¬ 
tion a stranger was discovered whose presence was evidently unwelcome to the 
family. 
In shape not unlike a very small millepede or woodlouse, it had long antennae 
and numerous legs. On examination, under a magnifying power of 8 diameters, 
the whole intestinal canal was seen distended with blood; this entirely dis¬ 
appeared in the course of fifteen minutes, proving the rapidity of digestion and 
assimilation. The mouth was armed with a formidable pair of pincers, and the 
forelegs with hooked claws. 
On making particular examination, every one of the swellings upon the dead 
leeches was found to have in its centre a punctured wound—“each in itself a 
death • ,5 the verdict was therefore soon decided, and the culprit placed in 
a preparation jar of water in order to watch its movements. It appeared to be 
actively engaged in seeking food ; probably living upon Infusoria, where larger 
prey is not to be obtained. It became however gradually more attenuated, until 
at the end of a week it died. 
The question naturally arises, how did this little destructive gain admission 
to the jar? Was the ovum attached to the body of a leech, or deposited under 
the skin, as is practised by the ichneumon flies upon caterpillars, or was the 
germ conveyed in the water supplied from the Thames ? as I have frequently 
noticed Monoculi and other animalcules in our unfiltered water ; but this seems 
the less probable as the water was changed daily, and the time required to hatch 
might have occupied several days. The subject is certainly one of some impor¬ 
tance, and commends itself not only to entomologists, but to all who keep such 
risky live-stock as leeches. 
R. Goodwin Mumbray. 
Richmond, S. JV. 
CAUSE OF CHANGE IN ESSENTIAL OILS. 
TO THE EDITOR OF THE PHARMACEUTICAL JOURNAL. 
“ We give a new name to a phenomenon, and fancy we have given a reason. Facts, 
not reasons, are as plentiful as blackberries.” 
Sir,—At folio 498. ‘ Pharmaceutical Journal,’ Vol. V., Mr. Charles Tomlin¬ 
son, Lecturer on Science, King’s College School, London, is reported to have 
stated that, “ if two oils pressed from the seeds were packed, one quite clean, 
and the other more or less contaminated with gum or mucilage, the latter 
would become more or less acidified, the gum, etc., apparently fermenting, and 
then setting up an acidifying action in the oil. This may explain some of the 
differences in the working and character of oils.” 
That gum, or mucilage, is ever present in the oils referred to has not been 
shown. The following are the results obtained by careful examinations of 
the precipitate, or deposit, invariably present in those oils :—The precipitate, 
or deposit, is insoluble in water, therefore cannot be mucilage nor gelatine. 
The precipitate, or deposit, is not coagulable by heat, therefore is not albu¬ 
men. The precipitate, or deposit, exhibits the properties of adipocere, and 
spermaceti in its solubility in boiling alcohol, fixed oils, and oil of turpentine; 
in its liquefaction by heat, and in forming saponaceous compounds with 
alkalies. Finally, the precipitate, or deposit, differs from spermaceti in its 
greater solubility in alcohol and oils. Yours respectfully, 
George Whipple. 
May 6 th, 1864. 
2 u 
VOL. V. 
