THI-: I'ki-.cii'i TIN ki- \< noN. 105 



2. The sensitivity of the ring test is very great. 



3. The titer of an antiserum is directly proportional to the 

 concentration of antigen within its limits of reaction. 



4. Total nitrogen determinations, at least, should therefore be 

 made on all antigens in order that comparable results may be 

 obtained. 



5. The specificity of the reaction of an antiserum decreases 

 with time. 



6. The H-ion concentration of antigen solutions affects the 

 reaction. Therefore buffered salt solutions should be used. 



7. Increase of salt concentration from .85 per cent, to 2.25 per 

 cent, decreases the titer of chicken antisera and tends to increase 

 their specificity. 



8. Filtration of antisera through Berkfeld filters usually does 

 not decrease titer nor change specificity. 



9. There is a variation in response of different animals of the 

 same species to the same protein. 



10. There was a general agreement in the group reactions 

 obtained in the majority of cases. This correspondence was 

 independent of the strength of the antisera used and occurred 

 in antisera produced in such different animals as rabbits and 

 fowls. 



11. There is an inhibition of the response of rabbit antisera 

 to other rodent bloods which is absent in the fowl. 



12. The principle of reciprocal relationships can be used to 

 test the agreement of the values obtained. 



13. The ring test is quantitatively specific for no heterologous 

 reaction ever exceeded the homologous reactions of the same 

 antiserum. 



14. The ring test when properly performed may give in- 

 formation of value to the student of animal relationships. 



The writer wishes to express his appreciation for the aid and 

 criticism of his work on the part of Dr. M. F. Guyer, Dr. A. S. 

 Pearse, Dr. H. C. Bradley and Dr. W. J. Meek of this University. 



LITERATURE. 

 Ascoli, M. 



'02 Ueber den Mechanismus der Albuminurie durch Eierehveis. Munchen 



med. Wochenschr., Jahrg. XLIX., pp. 398-401. 

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