Leeches that are venomous, thick about the middle, elongated, of slow locomotion, look fatigued, do not readily take to the part they are applied to, and capable of sucking only a small quantity of blood, should be looked upon as not belonging to the proper or the commendable type.
Then having seated or laid down the patient suffering from a disease which requires the application of leeches, the seat of bleeding, if not previously ulcerated, should be roughened by dusting it over with a composition of loose earth and pulverised cowdung. Then the leeches should be taken out of their receptacles and sprinkled over with water saturated with mustard seed and pasted turmeric. Then for a moment they should be kept in a basin full of water, and after they have regained their natural vivacity and freshness, they should be applied to the affected part. Their bodies should be covered with a piece of thin and wet linen, or with a piece of white cotton. The affected part should be sprinkled over with drops of milk or blood, or slight incisions should be made into it in the event of their refusing to stick to the desired spot. Other fresh leeches should be applied even when the preceding measures should prove ineffectual. That the leeches have taken to the affected part may be inferred from the mouths of the leeches assuming the shape of a horse-shoe, and the raised and arched position of their necks after they had become attached to the seat of the disease. While sucking, the leeches should be covered with a piece of wet linen and should be constantly sprinkled over with cold water.
A sensation of itching and of a drawing pain at the seat of the application would give rise to the presumption that fresh blood was being sucked, and the leeches should be forthwith removed. *
Leeches refusing to fall off even after the production of the desired effect, or sticking to the affected part out of their fondness for the smell of blood, should be sprinkled with the dust of powdered Saindhava (rock salt.)
After falling off, the leeches should be dusted over with rice powder and their mouths should be lubricated with a composition of oil and common salt. Then they should be caught by the tail-end with the thumb and the forefinger of the left hand and their backs should be gently rubbed with the same fingers of the right hand from tail upward to the mouth with a view to make them vomit or eject the full quantity of blood they had sucked from the seat of the disease. The process should be continued until they manifest the fullest symptoms of disgorging. Leeches that, had vomited the entire quantity of blood sucked as above, would briskly move about in quest of food if placed in water, while the contrary should be inferred from their lying dull and inert. These should be made to disgorge again. Leeches not made to emit the entire quantity of the sucked blood stand in danger of being attacked with an incurable disease peculiar to their genus, and which is known as Indramada. The leeches should then be put into a new pitcher, and treated as before laid down, after they had fully emitted the sucked blood.
* The leeches, though a blissful dispensation of Nature in themselves instinctively draw off the vitiated blood from a diseased part, attacking the healthy vital fluid (red blood) when the former has been completely tapped or sucked.
An ulcer incidental to an application of leeches should be rubbed with honey or washed with sprays of cold water, or bound up with an astringent (kashaya) sweet and cooling plaster, according to the quantity of blood removed from the part. *
The physician who is fully conversant with the habitat, mode of catching, preservation and application of leeches, can well aspire to cure the diseases which yield to them or in which their use is indicated.
* In case of full and proper bleeding (Yoga) the ulcer should be rubbed with clarified butter technically known as the Shatadhautam (lit: hundred times washed) Ghritam (clarified butter), or a piece of cotton, soaked in the same substance, applied as a compress over the part. The ulcer should be rubbed with honey in a case of insufficient bleeding, while it should be washed with a copious quantity of cold water if excessive bleeding (Ati-Yoga) should set in. Similarly in a case marked by the absence of any bleeding at all (Mithya-Yoga) a sour, sweet and cooling plaster should be applied over the ulcer.