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SCIENCE 



[N. S. Vol. XLII. No. 1074 



ymous with life. It was an ancient Celtic 

 custom to emphasize the inviolahility of a 

 treaty by having it written with the blood 

 of both clans mixed in one vessel. 



In the earlier systems of medicine, as 

 those of Asiatic countries, of Egypt and of 

 Greece, alterations in the composition of 

 the blood were held to be of great signif- 

 icance. In Hippocratic medicine the right 

 admixture of the foiir humors, the blood, 

 phlegm, yellow bile and black bile, consti- 

 tuted health, while wrong proportions or 

 distribution caused disease. This humoral 

 theory of disease, variously modified down 

 to our own time, has always fitted in well 

 with the practise of blood-letting, or ma- 

 king running issues, and with other deple- 

 tory measures. 



Blood-letting seems, however, to ante- 

 date all systems of medicine and to have 

 been one of the earliest therapeutic proce- 

 dures applied by primitive races. Leeches 

 have been used for this purpose sinee the 

 earliest times in Asiatic countries, espe- 

 cially in India, and let no one suppose that 

 their use has been discontinued in our day. 

 Dr. Shipley, the master of Christ's College, 

 Cambridge, writing in the British Medical 

 Journal,^ tells us that the Allies and Ger- 

 mans are now fighting on some of the best 

 leech areas of Europe, and goes on to state 

 that the traffic in leeches probably reached 

 its height in the first half of the nineteenth 

 century, that, for instance, in the year 1832, 

 57,500,000 of these annelids were imported 

 into France, 60,000 to 80,000 leeches a day 

 frequently leaving Strassburg for Paris, 

 having been shipped overland from Hun- 

 gary via Vienna. So great was the demand 



3 No. 2813, November 28, 1914, p. 917, and No. 

 2814, December 5, 1914, p. 962. These papers con- 

 tain much valuable information concerning the 

 medicinal leech, as also the curious history of 

 exotic leeches which in certain eastern countries 

 constitute a serious menace to the life of men and 

 animals. 



that the artificial cultivation of leeches 

 was taken up in various countries and be- 

 came a profitable industry. And now a 

 new use for leeches has arisen. Certain 

 glands surrounding the oral end of the di- 

 gestive canal of this annelid secrete a re- 

 markable substance which keeps blood from 

 coagulating and which has been named 

 hirudin. This substance is much used in 

 our laboratories to keep the blood of man 

 and animals in the fluid state. Leeches 

 have thus become an article of commerce 

 quite aside from their employment as deplet- 

 ing agents, and the demand is constantly 

 growing. We are at present greatly ham- 

 pered by our inability to obtain them from 

 Europe, as their importation has practically 

 ceased sinee the outbreak of the war. 



It is not my purpose to attempt to give 

 a history of blood-letting, even in abstract ; 

 the history of the subject is practically co- 

 extensive with the history of medicine it- 

 self. I must therefore content myself with 

 a few selections from historical writing 

 which will demonstrate to you that the in- 

 fluence of this method of treating disease 

 has been paramount since long before the 

 time of Hippocrates, whose writings furnish 

 one of the earliest prescriptions for blood- 

 letting, beginning with the direction to 



Bleed in the acute affections, if the disease ap- 

 pears strong, and the patients be in the vigor of 

 life, and if they have strength. 



In the latter part of the twelfth century, 

 when universities as we now know them 

 were coming into existence, there originated 

 in the School of Salernum the "Regimen 

 Sanitatis Salerni" or "Code of Health," a 

 poem written in Latin hexameter verses 

 and giving the medical notions of the day, 

 as derived from the Arabic writers in re- 

 gard to blood-letting, diet and personal 

 hygiene. The high value placed on the 

 "Regimen" may be seen from the fact that 

 it passed through some 240 different edi- 



