204 On the Operation of Medicinei. 



ftance wherein the milk either of a nurfe, or of 

 an animal, was tinged with madder or logwood. 

 This affords fome prefumption that the pigment 

 does not fubfift, in its proper form, in the 

 blood J but that it is recovered by a fubfequent 

 change, in the difpofition of its conftituent par- 

 ticles. And if one fubftance (lain the bones, 

 by being carried into contadl with them, another 

 may, in a way analogous, produce in them fra- 

 gility or diffblution. In the difeafe termed by 

 the French ergot^ and which, with apparent 

 reafon, is afcribed to the ufe of a fpecies of 

 unfound corn, the bones lofe the earthy matter 

 that enters into their texture, and become foft 

 and eafy to be broken. This effect is gradual, 

 and probably arifes from fome unknown quality 

 of the corn, which is either not fubdued by 

 digeftion, or refumed in the juices that circu- 

 late through the offeous veffels. A change in 

 the procefs of vegetation may communicate 

 a diffolvent power to an efculent feed. Muftard 

 acquires it by its natural growth, and is capable 



of the infecl which feeds on them, into a dye exaflly fimi- 

 lar to that produced by the powers of vegetation in the 

 pulp of the fruit. Cartheufer obtained from the cochineal 

 a moderately aftringent fpirituous extraft, amounting, in 

 weight, nearly to three fourths of the fubflance from which 

 it was prepared. Thefe fads exhibit a ftriking analogy 

 between digeftion and vegetation, as the produfts appear 

 to be the fame both in colour and quality. 



of 



