gS On Dr. MitchiWs Theory 



Fontana's Expcrhnents, the general exciting eaufe of pla<nie 



and peftilence had been left unexplored. 



Another oceurrence, duriiig that cxcnrficn, had direfte^ 

 his attention to the fubjecl of poifons. Dr. William M. 

 Rofs, one of the parly, had difcovered that the Rhus Toxko- 

 4cndro7i grew at the foot of tlie Blue Mountains. And a 

 parcel of the leaves and ftems of the plant were collefted 

 and carried home, with the intent of repeating Aldcrfon's 

 experiments with this venomous vegetable, on perfons af- 

 flifted with palfy. 



From this tour as he was returning to the city of New 

 Yoik, he learned with forrow at Paughkeepfic, a town eighty 

 miles diflant, that a malignant diftemper had broken out 

 during his abfence, and that among other perfons Dr. Mala- 

 chi Treat, then phyfician of the port, had been carried off 

 by it. HaRening back with all fpced, he faw and cohverfcd 

 with a number of phyficinns, and found them divided in 

 opinion, whether the yellow-fever, for fo the difeafe was 

 called, exifted in the city or not. The majority fccmed dif- 

 pofcd to doubt or deny the fa6l. A fliort time, however, 

 ■was fufficient to convince all perfons whatever, that a fad 

 and terrible malady had made its appearance arnong the in- 

 habitants. 



Impreflcd as he was with ideas about poifons, it appeared 

 to him at once, that the exciting caufe of the endemic fick- 

 ncfs of New York, was as much a poifon as thejluids fecretcd 

 hy the rattlc-fnake or the toxicodendron. There was a dif- 

 ference, however, between the venom of peftilence and the 

 poifons ftriftly denominated animal and <uegeiahle', becaufe 

 the two latter were always the cffe6l of vafcular and glandular 

 aftion with fecretion in living bodies ; whereas the former 

 was the refult of new combinations taking place in organized 

 fubftances during their putrefaction and decay, without any. 

 thing like a fecretory funftion. Herein, then, fccmed to 

 confifl the diflin£lion between what might be called Com- 



M o K 



