82 E. J. STIEGLITZ 



the injection. No iron passed through into the urine in this 

 experiment (K97), and therefore we can conchide that the more 

 rapid appearance of the convulsion is associated with the fact 

 that the animal was unable to get rid of the ferric salt through 

 the kidneys. In the other sublimate experiment carried out 

 (KlOl) one specimen of urine contained a very little iron four 

 hours after the injection of the ferric ammonium citrate. This 

 was a great deal less than normally passes. Therefore, in asso- 

 ciation with the results from the other groups of this series, we 

 have further proof that the route of iron secretion is through the 

 cells of the convoluted tubules. 



Group E (diphtheria toxin nephritis). Diphtheria toxin pro- 

 duces primarily a vascular or glomerular nephritis with hyalin 

 thrombi in the glomerular capillaries and cortical arterioles, 

 leucocytic infiltration and slight necrosis in the tufts, and a 

 certain amount of degeneration in the convoluted tubules (31). 

 Lyon (35) claims that diphtheria toxin produces almost wholly a 

 glomerular nephritis. In K106 of our series besides the glomer- 

 ular vacuolization the convoluted tubules appeared swollen and 

 granular, but there was no necrosis thereof. 



In experiments K106, K107, K108, we determined the max- 

 imal non-lethal dose (0.01 cc). In two experiments (K109, 

 KllO) the injection of iron followed that of the toxin twenty- 

 four hours later. In both cases there was a liberal secretion of 

 iron, recorded as triple plus in K109 and triple plus one and 

 one-half hours after the injection and plus four and a half hours 

 after the injection in KllO. Thus we see that the elimination of 

 iron is very little interfered with in this form of vascular or glo- 

 merular nephritis. 



From the above results we may conclude that the presence of 

 a distinctly localized tubular nephritis greatly interferes with 

 the secretion of iron, but a glomerular disease has relatively 

 little effect. Thus this series of experiments offers further cor- 

 roborative proof for the fact the iron (injected in the form of a 

 true ionized salt) is specifically secreted by the cells of the con- 

 voluted tubules. 



