1. Glomeruli possess properties which vary between Lewis and DA strains of rat.
2. These properties may account for differences in the expression of various forms of experimental glomerular injury.
3. The difference in susceptibility to Heymann nephritis in the Lewis strain was confirmed.
4. Chronic serum sickness induced by cationic human serum albumin led to capillary loop deposits in Lewis rats, whereas DA rats had mesangial deposits of rat immunoglobulin G even in control kidneys.
5. Lewis rats developed proteinuria after infusion of the polycation hexadimethrine whereas DA rats did not.
6. DA rats developed greater proteinuria after injection of puromycin aminonucleoside.
7. These results support the hypothesis that an individual's susceptibility to different forms of glomerulonephritis may result from their glomerular properties and not necessarily from their immune responses.