Dr. Bell on the Phyfiohgy of Plants. 429 

 this ftate accordingly it is thrown out on their 

 furface. Here the noxious part is excreted, but 

 part of the diluting fiuid is reabforbcd, to ferve 

 the purpofe of fccretion, which could not be 

 performed, unlefs the common juice, or fap, were 

 previoufly prepared. In the fame manner, m 

 the animal body, the faline and putrid mat'ter, 

 carried off by the urine, mult ,be liberally dilu- 

 ted, to prevent it from injuring the tender ftruc^ 

 turc of the kidneys ; yet, when it is h(t\y lodged 

 m the bladder, a part is reabforbed, and \hz 

 groffer excrementitious matter is alone thrown 

 out. Something of the fame kind happens in 

 the perfpiration of animals. They certainly' take 

 in fomething ufeful from the .furface of their 

 bodies, and this is probably performed by velTcIs 

 opening outwards, different from the common 

 exhalents. The great quantity of water, ab- 

 forbed during the ufe of the pediluvium, and 

 that Angular fymptom in diabetes, of the pati- 

 ent's voiding a much greater quantity of urine 

 than there is liquor taken in by the mouth, feeni 

 to confirm this aflcrtion. 



Neither in plants, nor in animals, can we 

 meafure the exad quantity perfpired or abforbed 

 we can only afcertain the excefs of the one over 

 the other, tor example, if a heliotropium, or 

 lun-flower, in one day lofe twenty ounces of its 

 weight, in another lofe nothing, and in a third 

 gain in weight ten ounces, it is only thence to 



be 



