Experimental nephrites in Guinea-pigs. ii 



Removal of one or both occipital lobes of the cerebrum does 

 not abolish labyrinthine nystagmus. True labyrinthine nystag- 

 mus has never been observed after complete decerebration, al- 

 though the slow deviation of the eye persists. The slow compo- 

 nent of nystagmus is of labyrinthine origin. The quick component 

 is probably of cerebral origin. 



The results suggest that the vestibular mechanism is con- 

 nected far more closely with the phylogenetically older motor 

 system (von Monakow) than with the phylogenetically newer 

 system. 



8 (617) 



• Experimental nephritis in guinea-pigs by subcutaneous 

 injections of chromates. 



By W. OPHULS. 



[From the Pathological Laboratory of Cooper Medical College and 



Stanford University.] 



After having determined that 1 centigram of bichromate of 

 potash is very nearly a lethal dose for guinea pigs of from 500- 

 750 gm., forty guinea pigs were used in an effort to produce, if 

 possible, lasting anatomic lesions in the kidneys by repeated in- 

 jections. Great difficulty was encountered in continuing larger 

 doses on account of the extensive necroses produced at the site 

 of injection. In the end it was found that a J— \ per cent, solu- 

 tion of chromate of potash to which an equal amount of carbonate 

 of soda had been added was most satisfactory, although still 

 quite irritating. As our experience has taught us that sublethal 

 doses are most effective in experiments of this character, injections 

 of one or one half centigram were used in one half of the experi- 

 ments and the doses crowded as closely as the animals would 

 tolerate; in other series smaller doses down to a quarter of a 

 milligram were employed and continued for long periods (in one 

 case for nearly two years). The immediate effect of the injection 

 of large doses in the guinea pig is the production of an albuminuria 

 which is usually quite limited in amount and the appearance in 

 the sediment of desquamated cells from the uriniferous tubules, 

 much more rarely of casts. The kidneys in the acute intoxication 



