On the Salivary Defiuxions in Horses, 351 



ver had been extensively cultivated ; and not occurring 

 at all in many places, where horses are pastured almost 

 altogether on clover ; sufficiently proved that opinion 

 to be erroneous. It was also imputed to the effects of 

 gypsum on plaister so frequently used to promote the 

 growth of clover, but the occurrence of it on many farms 

 where no plaister had been used, as well as its not 

 having occurred on many where it had been used very 

 copiously, proved this opinion equally incorrect with 

 the former. 



My friend Dr. William Baldwin of Wilmington in- 

 formed me, that a member of the Linnean society of 

 Philadelphia had supposed, that the ptyalism was caused 

 by a species of the euphorbia. He also politely favoured 

 me with a specimen of the species to which it was im- 

 puted, and gave me some information on the Euphorbia 

 Americana in general, which extensive knowledge of 

 botany enabled him to do. For the purpose of as- 

 certaining the fact, I procured a small quantity of 

 the Euphorbia maculata, and gave it to my horse en- 

 veloped in a small quantity of clover carefully gathered 

 stem by stem, and perfectly free from all other vegeta- 

 bles or any extraneous matter whatever. A preterna- 

 tural discharge of saliva took place in less than half an 

 hour. This experiment was frequently repeated, and 

 invariably with the same result. To prove that clover 

 did not contribute towards it, in some cases other grass 

 was used as an envelope with the same effect. And when 

 the horse was perfectly free from ptyalism, a conside- 

 rable quantity of clover carefully gathered without the 

 euphorbia was given to him, and no such effect was 

 produced. 



