May 25, 1917] 



SCIENCE 



505 



the council. This ' ' finger-signature ' ' indicates that 

 the act, to which it is attached in attestation, has 

 been discussed and definitively approved by those 

 whose mark has thus been put upon it. It is usual ' 

 in Cathay [China], when any contract is entered 

 into, for the outline of the fingers of the parties to 

 be traced upon the document. For experience 

 shows that no two individuals have fingers pre- 

 cisely alike. The hand of the contracting party is 

 set upon the back of the paper containing the 

 deed, and lines are then traced round his fingers up 

 to the knuckles, in order that if ever one of them 

 should deny his obligation this tracing may be 

 compared with his fingers and he may thus be con- 

 victed.i 



Professor Henri Cordier of Paris, the editor 

 of Yule's famous work, adds to this passage 

 a footnote relative to the history of finger- 

 prints, and commenting on the claim of Sir 

 W. Herschel, tersely remarks : 



Sir "W. Herschel was entirely vsrong; Mr. Faulds 

 protested against the claim of Sir W. Herschel, and 

 finally a Japanese gentlemen, Kumagusu Minakata, 

 proved the case for the Japanese and the Chinese. 

 None of these writers quoted the passage of Rashid- 

 eddin which is a peremptory proof of the antiquity 

 of the use of finger-prints by the Chinese. 



Indeed it is, and the observation that no two 

 individuals have finger-marks precisely alike 

 is thoroughly Galtonian. There is the earlier 

 testimony of the Arabic merchant Soleiman, 

 who wrote in a.d. 851, and who states that in 

 China creditor's bills were marked by the 

 debtor with his middle finger and index united 

 (see my History, p. 643). But we have more. 

 E. Chavannes, in reviewing my article in the 

 T'oung Pao (1913, p. 490), has pointed out 

 three contracts of the T'ang period, dated 

 A.D. 782 and 786 and discovered in Turkestan 

 (two by Sir Aurel Stein), which were provided 

 with the finger-marks of both parties, and con- 

 tain at the end the typical formula : 



The two parties have found this just and clear, 

 and have afiixed the impressions of their fingers as 

 a distinctive mark.2 



A clay seal for which no later date than the 



iSee H. Yule, "Cathay," new ed.. Vol. III., 

 p. 123, London, 1914, Hakluyt Society. 



2 See A. Stein, ' ' Ancient Khotan, ' ' Vol. I., 

 pp. 525-529, Oxford, 1907, where the three docu- 

 ments are published and translated by Chavannes. 



third century B.C. can be assumed, and which 

 bears on its reverse a very deeply and clearly 

 cut impression of the owner's thumb-mark, 

 has been brought back by me from China, 

 and is illustrated and described in the above 

 paper. I have also shown how the system was 

 developed in ancient China from magical 

 beliefs in the power of bodily parts, the indi- 

 vidual, as it were, sacrificing his finger in good 

 faith of his promises ; in its origin, the finger- 

 print had a magical and ritualistic character. 

 Sir "W. Herschel states that he fails to see 

 the definite force of the word " identification " 

 in the Chinese finger-print system. In his 

 opinion, there must be two impressions at 

 least, that will bear comparison, to constitute 

 " identification." He thinks, of course, one- 

 sidedly of the detection of criminals to which 

 the process has been applied by us, but never 

 in the East (for what reason, I have stated 

 elsewhere). Most certainly, the idea under- 

 lying Chinese finger-prints was principally 

 that of identification, as expressly stated by 

 Rashid-eddin and all Chinese informants. If 

 a doubt or litigation arose, all that was neces- 

 sary was to repeat the finger impression of the 

 contractor who had formerly signed ^he deed. 



B. Laufer 

 Field Museum, 

 Chicago, III. 



SPECIAL ARTICLES 



ON THE COLLOID CHEMISTRY OF FEHLING'S 

 TEST 



As familiarly known, when Fehling's solu- 

 tion is treated with a reducing substance, it is 

 generally expected that a bright red precipitate 

 will be obtained. Frequently, however, an 

 orange or yellow precipitate is obtained and in 

 certain instances nothing but a yellowish- 

 green or bluish-green discoloration results. 

 The attempts to account for these differences 

 are, for the most part, chemical in nature; it is 

 held that the red reaction represents a precipi- 

 tate of cuprous oxide, the orange or yellow ones 

 more doubtful suboxides or hydrated forms of 

 the oxide, while the character of the greenish 

 discolorations is left doubtful. It is often be- 



