Normal Precipitins 151 



(xi. 02) who tested the interaction of the blood of cold-blooded animals 

 with reference to haemolysis, agglutination, and precipitation He says 

 that " the results do not lend themselves readily to classification, and 

 from them no systematic conclusions can be drawn." 



In regard to precipitins he states that his " studies show conclusively 

 that normal precipitins are not uncommon, and may be compared with 

 the occurrence of normal haemolysins and agglutinins. The technique 

 of the experiments is simple : blood or body-cavity sera are obtained 

 after coagulation has taken place, and are rendered clear by filtration- 

 The clear products are mixed in given proportions, and the resulting 

 fluids are compared with controls of the mixed sera." 



No conclusions as to the relationship of these animals can be 

 obtained from these experiments. 



