78 THE PRECIPITIN TEST FOR BLOOD. 



tinguished exponent of the process,, and his recent work (pub- 

 lished in 1904) on " Blood Immunity and Relationship " com- 

 prises a complete record of his investigations made in 1902 on 

 certain blood-relationships amongst animals as indicated by 

 16,000 tests with precipitating antisera upon 900 specimens of 

 blood from various sources. This work also includes a section 

 dealing with the practical applications of the precipitin test for 

 blood in medico-legal practice, together with some investigations 

 carried out by Graham-Smith and Sanger." 



The principle of the test, as applied in medico-legal work, 

 depends upon the fact that if into the body of any animal A the 

 defribinated blood of another animal B is injected, after the 

 lapse of a short time the blood of the animal A is found to be 

 hemolytic or toxic to blood of the species of the animal B. 



The precipitin test was officially recommended by the 

 Ministers of Justice in Germany and Austria in October, 1903, 

 and as early as 1904 it had been used in the Courts of Law of 

 France, Italy, Roumania, Turkey, Egypt, Ireland, and the 

 United States of America. 



England, with characteristic conservatism in matters touch- 

 ing her legal system, had not yet adopted it, this neglect being 

 due, so the exponents of the test affirm, not so much to a distrust 

 of the reliability of the new method, as to an ignorance of its 

 existence.! 



To the list of countries in which the test had been applied 

 with success South Africa also was added in 1904,! for about 

 the middle of that year the Government Veterinary Surgeon at 

 Grahamstown afforded me every assistance in the preparation of 

 various anti-sera, and we placed ourselves in direct communica- 

 tion with Dr. Nuttall, of Cambridge, whose advice was of very 

 material assistance. 



In a small town like Grahamstown it was extremely difficult 

 at times to obtain human blood serum, so that at first the rabbits 

 used as media (and the rabbit is par excellence the animal for 

 this purpose) were given intraperitoneal injections of pleuritic 

 and peritoneal exudations, hydrocele fluid, and albuminous urine 

 preserved with chloroform instead of blood-serum injections. 

 The anti-sera obtained in this manner appeared to be rather 

 weak, and much less potent than that obtained by intravenous 

 injections of blood-serum. 



In the latter process blood serum is introduced by a fine- 

 needled syringe into the marginal ear-vein in small quantities at 

 certain intervals, and yields more powerful anti-sera, the human 

 sera used for the purpose being chiefly derived from post-mortem 

 cases, preserved by means of a small addition of chloroform, 

 and kept in sealed tubes. 



* Journal of Hygiene, vol. III., 1903. 



t See paper by Prof. McWeeney on " The Biological method of 

 differentiating blood stains " in Report Brit. Ass. for Adv. of Sc. 1908, 

 p. 882. 



J Vide South African Law Journal, pt. I., vol. 24, pp. 4 — 12. 



