Tests with Precipitins 403 



Fig. 5 Illustrates the action of acids and alkalis on the formation of the specific 

 preeipitum. All the tubes contain -Sc.c. of human serum dilution (1 : 21) in salt 

 solution. Nos. 15 contain 5 to 1 drops of 1 in 10 Hydrochloric acid. No 

 precipitates have been formed. No. 6 did not receive any acid or alkali. Nos. 711 

 contain 15 drops of 1 in 10 sodium carbonate solution ; the quantity of preeipitum 

 shows a decrease along the series. Nos. 1222 have been similarly treated but 

 received drops of 1 in 100 acid and alkali respectively. The preeipitum is seen to 

 increase from 12 to 16 and decrease from 18 to 22. The slight clouding above the 

 preeipitum in each case is due to bacterial growth, the tubes having stood 48 hours. 



We are indebted to Walter Mitchell, our laboratory attendant, for the 

 time and attention he has bestowed on the photographing of these specimens." 



Graham-Smith and Sanger (p. 260), as the result of their investi- 

 gations, reach the following conclusion, which I can but endorse : 



" These experiments have led us to the conclusion that with sufficient 

 materials, and due precaution to exclude the various sources of error, 

 there are but few conditions met with in forensic practice under which 

 human could not be readily differentiated from other bloods. By this, 

 however, we do not mean to imply that a considerable acquaintance 

 with the action of precipitating antisera on blood solutions is not 

 necessary in the successful application of this test." 



That this conclusion is fully justified is proved by the official 

 recognition of the precipitin method in forensic practice by foreign 

 Governments. Prof. Uhlenhuth (19. ix. '03) informs me that the 

 method has been recommended by the Ministers of Justice in Germany 

 and Austria, and that it has been officially recognized by the Govern- 

 ments of Egypt and Roumania. 



I herewith append a copy of the Order issued by the German 

 Authorities, the same having appeared in the Medicinalblatt fur Medi- 

 ciner und medicinische Unterrichtsangelegenheiten No. 17 (1. X. '03): 



BERLIN, W. 64, 



den 8. Sept. 1903. 



WlLHELMSTRASSE 65. 



Der Minister des geiitlichen Unterrichts 



und Medicinalangelegenheiten. 

 U. I, No. 12328 M. 

 Der Justizminister, 

 I. No. I, 5283. 



Von dem Stabsarzte Professor Dr. Uhlenhuth in Greifswald ist eine 

 Methode der Blutuntersuchung vermittelt worden wolche es ermoglicht, die Art 

 des zu untersuchenden Blutes festzustellen und namentlich Menschenblut mit 

 Sicherheit von Thierblut zu unterscheiden. Bei der Behandlung des zu uuter- 



262 



