388 Medico-Legal 



bloods in this respect (ox, sheep, goat). The very large number of 

 bloods, both of Bovidae and Cervidae, examined by me and reported 

 upon in part in earlier papers (see pp. 183 192, 252 258) show 

 that either anti-cervine or anti-bovine sera will usually suffice for the 

 identification of a blood as belonging to the group Pecora. I suspect 

 therefore that Uhlenhuth's anti-sheep serum used in Case 12 must have 

 been weak, for I have obtained quite marked reactions with roebuck 

 blood upon the addition of anti-sheep serurn, although the reaction was 

 naturally less intense than with the sheep blood. 



In medico-legal work, Uhlenhuth states that he would proceed to 

 test the blood dilutions with the different antisera in succession, until 

 a positive reaction is obtained. I should however warn against adding 

 different antisera in succession to the same blood sample. The reasons 

 being that no time limit is observable for the reaction which one or the 

 other antiserum may give, the first antiserum may give a "mammalian 

 reaction" which will be attributed to the last antiserum added, or finally, 

 the increasing serum concentration due to having added several antisera, 

 will mask the reaction. 



I have already drawn attention to the fact that over-powerful anti- 

 sera may be a source of error (p. 74) in medico-legal work, as is also 

 stated by Uhlenhuth. Reaction should take place within a few minutes 

 after antiserum and blood-dilution have been mixed. Uhlenhuth properly 

 dwells upon the necessity of every antiserum used being provedly effective, 

 and to insure this he considers, as does also Ziemke, that the preparation 

 and testing of antisera for medico-legal purposes should be under State 

 control. The use of weak antisera, which require a period of 24 hours, 

 or the like, to exert their action should certainly be condemned for 

 medico-legal work. A great many bloods may react to an antiserum 

 after such a lapse of time, and there may be bacterial development 

 (see p. 86). I have not infrequently observed, and this has been con- 

 firmed by Ziemke, that quite a marked clouding may occur which does 

 not necessarily lead to a deposit after 24 hours. This result is recorded 

 in my protocols, no deposits being noted at times under bloods which 

 gave even marked cloudings. In my short tables which summarise the 

 contents of those at the end, I found it necessary to give, for instance, 

 equal value to, say a marked clouding, leading to little or no deposit, 

 and to a faint clouding leading to a deposit. 



In my investigations, of course, the main thing was to see if any 

 blood-relationship could be established, the question of identification 

 was of secondary importance. 



