Leeches were used in the treatment of many pediatric conditions until relatively recently. Many physicians prescribed leeches, especially in the treatment of the purported symptoms caused by teething. William Moss,1 for example, advised applying two or three leeches at one time on the foot or heel of teething infants where "bleeding is a remedy much to be depended on when the symptoms of heat, fever, drowsiness, and startings are urgent."
The following is an excellent description of the indications for leeching in children, as given by Dr. James Kennedy in 1825:
Leeching, so as to abstract blood from a particular part sustaining inflammation, fulness, or pain, is very useful in many diseases especially those of children. . . . When the leech is of the right or medicinal kind, its body has a blackish brown colour, marked on the back with six yellow spots, and edged with a yellow line on each side:—these spots, however, as well as the lines, grow faint and almost disappear at certain seasons. . . . The mouth forms, as it were, the body of a pump and its tongue the sucker; and, by the working of this . . . mechanism, the blood is made to rise up into the conduit which conveys it to the animal's stomach. . . .
Leeches may be employed in every case where topical bleedings are required, or where venesection cannot be performed. Before applying them, all the parts should be carefully washed;—first, with hot water and soap, for the purpose of removing, as much as possible, the particles of the cutaneous excretion which the leech instinctively dislikes, especially if impregnated in any degree with the odour of medicine;—and secondly, with milk and water as warm as can be endured, with the object of stimulating the superficial vessels and filling them with red blood.