342 COW-TREES. 



the ground, striking roots, but very seldom put- 

 ting out branches ; and it will run in that way to 

 the distance of five hundred feet ; but when it en- 

 counters trees, it climbs up the stems and spreads 

 among the branches. The quantity of juice in an 

 old plant amounts to nearly two thirds of the en- 

 tire weight of the plant. When recent, it very 

 much resembles milk, and when consolidated it is 

 Indian rubber. 



It is not very clearly ascertained to which of the 

 two families the Palo de vacca, or cow-tree of 

 South America belongs ; but, the people resort to 

 that tree, fetch the juice in pitchers, and use it for 

 the same purposes as animal milk. Nor is it a 

 little curious that, in those parts of the world 

 where, on account of the parching up of the grass, 

 the milk of domestic animals is not so easily pro- 

 cured as in more temperate climates, there should 

 be an abundant, and by no means a bad substitute 

 in the juices of trees. 



But besides their eatable juices, these plants 

 have a very deleterious principle, which in some of 

 the species is a very virulent poison. That prin- 

 ciple is Strychnia, so called from being first found 

 in the kernels of the Strychnos nux vomica and 

 Strychnos ignatiana; but it is also found in the 

 Upas, and in other species : and it is not a little 

 remarkable that, while some of the species of 

 Strychnas are so deadly, others are valuable medi- 

 cines. These coincidences in some respects, and 

 differences in others, should teach us to be cau- 

 tious in not generalizing to any of those artificial 

 tribes of organized being, any property which we 

 have discovered only in some members of that 

 tribe. The products of organization are quite 



