The Bulletin of the United States Fish Commission 1882
Artificial culture of medicinal leeches and of species of Helix.
Referring to your formerly expressed intention to make at the United States fish ponds a trial of breeding the Hirudo medicinalis, or medicinal leech, and other species of Hirudo, I beg to remind you of the matter, deeming this season most favorable for the importation of a number of propagative animals. It will require for the first trial not more than 200 to 300 or 400 individuals and I have found a little pond about 36 inches by 16 inches the best size.
I recommend for this purpose the green species Hirudo officinalis, from Southeastern Europe (Hungary, Croatia, Bosnia) and the brown species, Hirudo medicinalis, from Southwestern Europe, (Italy, Spain, France, and some few parts of Southern Germany). There are some other different kinds coming from Asia Minor, Egypt, Algeria, and Morocco; but I think the above named are the best for breeding and medicinal purposes. They have more eggs in the cocoon (12 or 15 to 20) and are not subject to many diseases, and they are hardy enough for our climate. I must explain to you that the so-called marketable Hirudo that we find in the drug stores is not the propagative one; it is too small, too young for this purpose. It requires a larger size - four to six year old ones of 4 inches to 5 inches in length. I kept in my ponds as breeders a large size, 5 inches to 6 inches long and 1 inch thick, (after feeding). They call them in Austria, Germany, "mother leeches;" in France, sang-sue-vaches.
On this occasion I believe it my duty to call your attention to the special breeding of another animal, which is extensively carried on in Italy, Spain, France, Austria and South Germany, namely, that of the snail Helix pomatia. This breeding is as yet quite unknown in America, although large quantities of Helix aspersa are brought to New York from private establishments each winter.
How extensively the breeding of helices is carried on in Southern Europe, France, Austria, and South Germany (not at all in Central and Northern Germany), you may gather from the circumstance that Marseilles ships more than 10,000 to 15,000 hundredweight for Paris and London; Genoa the same quantity.
Austria breeds a great many; Bavaria, Wurtemberg, and Baden, too, for the Vienna, Munich, Swiss, and Paris markets.
When a young boy, I collected them by the thousands in the valleys and little hills of the Black Forest Mountains and in the sunny meadows of the Upper Rhine, where I found many other kinds of Helix.
I myself raised some of them years after, by the thousand, in my own business, and these were the Helix pomatia out of the vineyards, Helix rhodostoma from France and Italy; H. aspersa (France) and H. vermicularis.
Not much room is needed to keep about 1,000 or 2,000 living in, and for breeding purposes, a box, 20 feet by 5 feet by 2 feet in depth, sunk into the ground and covered with a wire screen frame, will answer to raise about 40,000 to 50,000, with a few square yards of ground to plant the food for them.
Washington D.C. February 9, 1882.