In a large series of suprarenalectomized rats, hemolysin formation, to a fixed amount of sheep cells injected intraperitoneally (1 cc. of a 10 per cent suspension), was studied 48 hours, 7, 14 and 28 days after operation. The hemolysin formation was studied in suprarenalectomized rats injected 2 weeks following the operation, with one-twentieth and ten times this amount. Hemolysin formation in rats traumatized by tearing the perisuprarenal tissue and injected 2 weeks after the operation with 1 cc. of a 10 per cent suspension of sheep cells was studied and the results compared with those in the normal control rats. The effect of the operative procedure was controlled by removing one kidney in a series of rats and determining the antibody response to sheep cells.
1. Bilateral suprarenalectomy in rats subsequently injected intraperitoneally with 1 cc. of a 10 per cent suspension of sheep cells resulted in a depression of hemolysin titer during 5 weeks following the operation, the depression being most marked during the 1st week.
2. Bilaterally suprarenalectomized rats injected intraperitoneally 2 weeks after operation with 1 cc. of undiluted sheep cells gave hemolysin titers higher than did normal rats.
3. The quantity of antigen necessary to yield the maximum titer in suprarenalectomized rats 2 weeks after operation is ten times the quantity necessary to yield the same titer in normal rats.
4. Traumatization of the perisuprarenal tissue in rats produced the same effect on the antibody-forming capacity as suprarenalectomy.