634 
THE BREEDING OF LEECHES. 
TO THE EDITOR OF THE PHARMACEUTICAL JOURNAL. 
Sir,—Dr. Thomson, in the ‘ London Dispensatory ’ of 1818, says that leeches 
.are oviparous, and all the ova are discharged in one involucre, near the surface 
and the margin of pools, and are hatched by the heat of the sun. 
The sellers of leech aquaria say, that if shingle and aquatic plants, water and 
leeches are placed in them, they will breed there. I have endeavoured several 
times to get the valisneria to grow, but have never succeeded, as I have not had 
earth with it; the anacharis grows luxuriantly, but discolours the water. 
On the 18th of August, 1869, I placed fifty leeches, which were just received 
from Fitch and Nottingham, in an aquarium, with about three inches of shingle 
and shells at the bottom of it, but no plant, and in about a month afterwards, 
I had all taken out and well washed under a water-tap ; as the leeches were very 
healthy, it was let alone for about two months, when the water was gently 
poured off, and refilled w T ith water from an artesian well. To economize counter 
room, my aquarium is placed upon a case, and six inches from a gaslight; over 
it is suspended a gaslight, which throws a good deal of heat downwards upon 
the side of the aquarium. About ten days ago, when I was passing the end of 
the counter, and the light shining through the water, I observed some thread¬ 
like living objects, about half an inch long, just opposite the gaslight, where 
the aquarium was warm, but soon after the light was extinguished they disap¬ 
peared-; two evenings afterwards they came to the same place, and had now the 
habits of the leech, by adheriug to the glass with the anal extremity, and moving 
about continually, until they adhered to it by the mouth. I next saw others of 
apparently another hatching, as they were only about three-eighths of an inch 
long. Two nights ago my assistant called my attention to something under a 
pebble, which seemed to move ; and last night, when he showed me a similar 
appearance under a stone, I took the stone out to see whether the substance ad¬ 
hered to it, but found it loose, and it followed the movement of the water, and 
was of a light filmy appearance, struggling with life, which separated into two 
parts, several leeches becoming disentangled, floated away, when the two parts 
went to the bottom, numbering apparently about thirty. 
From what I have noticed, the leeches have deposited their ova under the 
pebbles, and had been hatched by the heat of the gas. 
I shall be glad if any of your readers can inform me how and where I could 
get a valisneria plant, with earth to its roots, as it does not easily take root 
after being taken out of the earth. 
I remain yours respectfully, 
T. Colton. 
Selby, February 18, 1870. 
AN APOLOGUE OF CORPOREAL AND COSMICAL INFINITY. 
BY FRA OLLjE.—PART I. AB OVO. 
“ Sermons in Stones.” 
Some disquisitions on the constitution of matter, that have recently appeared 
in the 1 Pharmaceutical Journal;’ have reminded me of a conversation (of which 
I have fortunately preserved the notes) upon a kindred subject; a conversation 
which interested me much at the time, and which may possibly prove interesting 
to some of its readers. I do not, of course, pretend to have preserved every¬ 
where the precise language that was used ; but substantially, and in all essen- 
