Differentiation between stains of human blood and blood of monkey

The precipitin tube test fails to differentiate between blood stains of closely related animals such as man and monkey because of the close similarity between antigenic determinants of serum proteins of such closely related species. The quantitative precipitin technique cannot be applied to forensic work. This paper cites a case where definite opinion on the species of origin of some blood stains suspected to have come from a monkey was possible. In the method used, extracts of the questioned stain were tested with similar extracts of known human and known monkey blood stains against human globulin antiserum, by comparative double diffusion method in agar gel on microslides.