64 The Precipitii}.^: Methods 



frequent insolubility of blood stains, which in this climate may be dried 

 at a temperature of 115° Fahr. or even more. Blood stains usually don't 

 give the spectroscope test when extracted. If more dried or older, they 

 successively refuse to give the haemin and, I believe, the guaiacum tests." 

 It will be seen from my tabulated results that bloods sent to me from 

 h(jt coimtries dried on filter-paper not infrequently refused to go into 

 solution in saline. Where I had to deal with such bloods I allowed 

 them to remain some hours in salt solution at 37° C. Some bloods 

 hoAvever refused to go into solution even after 24 hours under these 

 conditions. Such bloods naturally gave no reactions. Other bloods 

 from the same source gave full or feeble reactions. This difference in 

 behaviour may depend upon the different temperatures at which they 

 were dried. These observations are of importance from a medico-legal 

 standpoint. I did not find it advisable to use a weak soda-solution 

 (0-1 to iVo) as recommended by Uhlenhuth (17 Oct. 1901, and by 

 Ziemke, p. 732), for the reason that it frequently yielded solutions 

 which gave rise to a cloudiness on the addition of any antiserum S the 

 cloudiness being in some cases quite marked, and sufiicient to obscure 

 the mammalian reaction to which I first drew attention, and which will 

 be presently referred to. In the examination of the large number of 

 blood samples investigated it seemed scarcely worth while to try the 

 method recommended by Ziemke (17 Oct. 1901) of extracting with 

 cyanide of potash solution. He does not state the strength of the 

 cyanide solution used as a solvent, but claims that it has even a greater 

 solvent action than the soda solution for bloods which will not go into 

 solution in saline. Ziemke adds a few crystals of tartaric acid to the 

 cyanide-blood solution, shakes the fluid and tests continuously with 

 red and blue litmus paper, until the reaction is almost neutral. The 

 solution is now decanted and filtered. If the solution is to remain 

 clear it must be slightly alkaline. The solution is now diluted to the 

 degree desired and tested with antiserum in the usual way. The 

 method of Ziemke was too complicated for my purposes, although it 

 may be of use medico-legally. IThlenhuth has also recommended the 

 use of .saline chloroform -water for extracting difficultly soluble blood 

 stains. In my investigations I however preferred to pass over the 

 insoluble bloods, that is bloods insoluble in salt solution, and this for 

 the reason that, in the case of chloroform, slight cloudings frequently 

 occurred in solutions Avhere all the chloroform was not driven off, 

 upon the addition of antiserum of any kind. These cloudings due to 



' See furtlier in tlie section relating' to the modico-lc^al application of tlie test. 



