DIETETIC PLANTS. 343 



addition of one part of poor cheese and three parts of chalk, 

 is kept at a temperature of 80 F. for two or three weeks, it 

 gradually becomes filled with crystals of lactate of lime. After 

 purification by recrystallisation, these crystals are treated witK 

 one-third of their weight of sulphuric acid. The residue being 

 then digested in alcohol, the lactic acid is dissolved, and sul- 

 phate of lime left. On the evaporation of the alcohol, pure 

 lactic acid remains. 



Lactic acid exists, ready formed, in some plants ; thus it 

 may be obtained from nux vomica in the state of lactate of 

 lime. It exists in the animal body, as in the fluids of the 

 muscular tissue. 



PLANTS EMPLOYED TO FURNISH ARTICLES OF FOOD, 

 ARRANGED IN A BOTANICAL ORDER. 



DICOTYLEDONOUS PLANTS. Sub - class Thalamiflorce 

 Ranwtculacece, Buttercup order. Though numerous species 

 of the genus ranunculus, from which the Ranunculacece derive 

 their name, abound in the pastures of Europe and North 

 America, there is hardly one of this family that can be 

 said to afford nourishment to domestic animals. On the 

 contrary, there prevails generally throughout this family a 

 remarkable acrimony, and not a few narcotico-acrid poisons 

 figure amongst them. Of these it is sufficient to mention the 

 aconite (Aconitum napellus),\hQ stavesacre (Delphinium staph- 

 isagria), the Christmas rose (Helleborus niger). It appears, 

 however, that the acrimony of the common buttercups, or 

 crowfoots of our pastures, is much diminished or destroyed by 

 heat. It is not impossible, then, that such plants may be 

 rendered innocuous, if not useful, by a proper preparation. 

 There are two plants in this natural order which may be 

 mentioned under the head of nutritive substances namely, 



