‘Our chief hope seems to lie in India.’ These words I wrote in October 1914, and my hopes were justified. Owing to the energy of Dr. Annandale of the Indian Museum, and the anxious care of the authorities of the P. & O. Company, I was able to land, early in the present year, a consignment of many hundred Limnatis granulosa—in sound health, good spirits, and obviously anxious to do their duty.
Leeches are still used much more than the public are aware. One pharmaceutical chemist in the West End of London tells me he sells between one and two thousand a year; and as they are bought wholesale at about one penny each and sold retail at about sixpence, there is some small profit.
Fig. 50.—Head of a leech, Hirudo medicinalis, opened ventrally to show the three teeth and the pharynx p, with its muscles; s, a nephridium.
Leeches were well known to the ancients, and it would be easy to quote case after case from the classical medical authorities of their use in fevers and headaches and for many ill-defined swellings. They were frequently used for blood-letting where a cupping-glass was out of the question. With his curious uncritical instinct, Pliny records that the ashes of a leech sprinkled over a hirsute area or formed into a paste with vinegar and applied to the part will remove hair from any region of the body. Leeches were also used by the Greek and Roman physicians in angina—especially when accompanied by dyspnoea.
Probably the traffic in leeches reached its height in the first half of the nineteenth century. Harding reminds us that in the year 1832 Ébrard records that 57,500,000 of these annelids were imported into France, and by this time the artificial cultivation of leeches had become a very profitable industry. Although in a small way leeches may have been cultivated in special ponds in Great Britain, the English never undertook the industry on a large scale. In Ireland the natives used to gather the leeches in Lough Mask, and other inland lakes, by sitting on the edge of the pool dangling their legs in the water until the leeches had fastened on them. But the native supply was totally inadequate, and the great majority of leeches used in this country were then imported. In 1842 Brightwell mentions a dealer in Norwich who always kept a stock of 5000 of these annelids in two large tanks. The traffic, as we have seen, was very considerable.
The French leech-merchants recognised five classes, as follows:—
1. Les filets ou petites Sangsues, qui ont de un à cinq ans;
2. Les petites moyennes, qui ont de cinq à huit ans;
3. Les grosses moyennes, qui ont de huit à douze ans;