200 University of California Publications m Zoology [Vol. 11 



It seems that Themison, the founder of the ancient medical 

 sect of the Methodici, and an eminent physician of Laodicea, in 

 Syria (eire. 100 b.c), was the first to make use of leeches in 

 medical practice. According to Houghton (1863), the ancient 

 Hebrews and Orientals generally do not appear to have been 

 acquainted with this method of blood-letting. Abundant evidence 

 is available, however, that the Greeks and Romans were familiar 

 with the practice and made use of it freely. 



At one time the leeches were considered to be reliable weather 

 prognosticators. If a wind was about to rise, ' ' the poor prisoner 

 galloped through its limpid habitation with amazing swiftness"; 

 while, if a storm was at hand, the leech crawled up the side of 

 the dish and, lodging out of the water, ' ' discovered great uneasi- 

 ness in violent throes and convulsions." So staunchly held were 

 these views that experiments to test their validity were conducted 

 by Valmont de Bomare (1776), Vitet (1809), and Bonnet (1775), 

 which showed that the leeches were in no wise reliable weather 

 indicators, nor were they likely, as was held by many, to replace 

 the barometers of that period. 



There is a striking meagreness of recent literature devoted 

 to the behavior of the Hirudinea. The contributions of Darwin 

 (1883), Hofmeister (1845), Parker (1901), Smith (1902), 

 Adams (1903), Holmes (1905), Harper (1905), Jennings (1906), 

 Yerkes (1912), and a number of others on the behavior of the 

 earthworm have established so thoroughly the fundamental fea- 

 tures of annelid behavior that it is perhaps for this reason that 

 the leeches have been neglected. The most of the earlier liter- 

 ature has been found to deal largely with the questions of struc- 

 ture and classification, little attention being given to the natural 

 history of the leeches. 



Several extensive monographs have been devoted to the gen- 

 eral considerations of leeches. The earliest of these of signifi- 

 cance is that by Moquin-Tandon (1827). The same author 

 several years later (1846) revised and enlarged his earlier work, 

 and this revision constitutes a classic in the literature on leeches. 

 Another extensive writer on leeches is Ebrard, to whose credit 

 are two volumes: the first, Des sangsues, considerees au point 

 de vue de I'economie medicale (1848) ; the second. Nonvelle 



