ENDOCRINE FUNCTION OF THE THYMUS GLAND 



319 



TABLE 2 



Showing the precipitin reaction of the antithymus serum with the extracts of different 



rat organs 



First reading (4 to 6 hours) 



Kidney . . 

 Spleen . . . 

 Testes. .. 



Brain 



Thymus . 



+ + + + 



+ + 



+ + 



Second reading (16 to 18 hours) 



Kidney . . 

 Spleen . . , 

 Testes . . . 



Brain 



Thymus. 



+ + 



+ + + 



+ + 



+ + i + + + 



+ + 

 + + + 

 + + + 



+ + + 



+ + 

 + + + 

 + + + 



+ + + 



+ + 

 + + + 

 + + + 



+ + + 



+ + + , marked sedimentation. 

 + + , less marked, but easily recognizable precipitation. 

 + , slightly positive precipitation. 

 — , negative precipitin reaction. 



Another technique for the precipitin reaction which is gener- 

 ally used in serological work (namely, mixing the antiserum with 

 about an equal amount of some dilution of antigen injected for 

 the production of the antiserum, with resulting turbidity and 

 rapid flocculation) was tried with the material used in the above 

 tests, but the reaction was inconspicuous in all cases. 



Using as precipitinogen, serum from a normal rat, diluted ten 

 times, instead of organ extract, all the test-tubes, to which from 

 one to five drops of the antithymus serum had been added, failed 

 to show either precipitation or sedimentation. 



From the result mentioned in table 2 we can tentatively con- 

 clude that the antibodies which are present in the antithymus 

 .serum are not so specific as we are taught to believe by some 



