ORGAN (TISSUE) DIFFERENTIALS 543 



which was tested with the immune serum, was derived from cancer of the 

 same organ as that which served as antigen for the preparation of the 

 immune serum, than if cancer of a different organ was used; but positive 

 results were obtained in many cases also with autolysates from cancer 

 originating in a different organ. Likewise, the serum of cancerous patients 

 reacted with such immune sera, and in this case also there was an indica- 

 tion of an organ specificity. No reactions were found, as a rule, with the 

 sera of non-cancerous persons. It seems, then, that in carcinoma a protein 

 antigen is present, which possesses a certain degree of organ specificity 

 combined with species specificity. 



9. It is possible to produce specific immune sera also against spermatozoa, 

 or, rather, against spermatic fluid, as well as against testicle and epididymis. 

 According to Ohki, the immune sera against the latter organs owe their origin 

 to spermatozoa, or to precursors of spermatozoa, which are found in the 

 tubules of the testicle and epididymis. He finds that the anti-spermatozoa 

 sera produced in rabbits react most strongly with spermatozoa from the same 

 species which served as donor, but that a weaker reaction may take place 

 also with the sperm-antigens from heterogenous species. Even between 

 spermatozoa of birds and mammals and their immune sera an interaction 

 may occur. Both precipitin and complement fixation reactions were used in 

 these tests. They are, on the whole, specific for the spermatozoa present in 

 testicle and epididymis, although the immune sera against these cells may 

 also react with the blood serum of the donor species ; but the latter kind of 

 antibodies can be removed by means of selective absorption, following which 

 the antisperm antibodies alone remain in the immune serum. It is also 

 possible to remove by means of specific absorption, through previous addition 

 of spermatic fluid, the antisperm fraction of the immune serum ; but while, 

 in this case, according to Hektoen and Schulhof, the antibodies against blood 

 serum are also removed, according to Strube the precipitins for blood serum 

 remain intact in the immune serum. It may then be stated that distinct 

 antibodies may be produced against a spermatic fluid and against a serum 

 fraction present in the antigen. On the other hand, according to Ohki, it is 

 possible to obtain immune sera against spermatozoa which do not react with 

 the serum of the donor. If we accept the conclusion that it is really the 

 spermatozoa, as such, against which the immune sera are produced, we 

 should have to assume that the spermatozoa contain both organ and 

 organismal differentials, or rather their precursor substances. They would 

 contain organismal differentials or their precursors, because the immune sera 

 react most strongly with spermatozoa of the donor species ; they are organ- 

 specific because an immune serum against mammalian spermatozoa reacts 

 also with avian spermatic fluid. While also in this instance the organ dif- 

 ferentials seem to be more prominent than the organismal differentials, they 

 are less so than the differentials of the lens of the eye. It is, furthermore, of 

 interest that according to Ohki not only heterogenous spermatozoa may 

 serve as antigens, but also those of homoiogenous, or even of autogenous, 

 origin. 



