106 



MATERIA MEDICA. 



Fig. 28. 



pith of the trunk ; this is agitated 

 in water, to which it imparts its 

 starch ; this subsides, and is passed 

 through a sieve, when the farina 

 is deposited on standing, and then 

 dried ; this is common sago. It 

 is in grains of unequal size, of a 

 yellowish colour. The finest kind, 

 called pearl sago, is refined by 

 the Chinese ; it is in small round 

 grains, whitish, hard, and some- 

 times translucent, with no odour, 

 and a slight taste. It consists 

 almost entirely of pure starch ; 

 insoluble in cold water; requires 

 long boiling. — Uses and modes of 

 preparation, the same as tapioca. 



CLASS XX. — DILUENTS. 



" Mild liquids which dilute the contents of the stomach and 

 bowels ; and which, entering the blood-vessels, renders the blood 

 thinner, and, at the same time, dilute the secretions." Water is the 

 only liquid, strictly speaking, which can be used for these purposes ; 

 water is, in fact, the great diluent of nature. The additions which 

 are usually made, are for the purpose of imparting flavour, or ren- 

 dering it more nutritive. Diluents are useful in inflammatory dis- 

 eases, — in cases of acrid poisons, — as adjuvants to emetics, &c., 

 also to restore a proper degree of fluidity to the blood. The de- 

 mulcents form the best diluent drinks. 



CLASS XXL — ANTACIDS. 



" Medicines which combine with and neutralize acids." Their 

 action is entirely chemical. Although all salifiable bases are ant- 

 acids, the only ones employed remedially are the alkalies, alkaline 

 earths, and alkaline carbonates. They do good by removing excess 

 of acid in the stomach and bowels, which is frequently the cause of 

 disease, as colic, diarrhosa, &c. They are also useful in the uric 

 acid diathesis, where there is a tendency to gout and gravel. 



Magnesia. 



One of the most valuable of the antacids ; — very powerful, in 

 consequence of its low combining number ; used extensively in the 

 colics and diariiioeas of children, either alone, or combined with 

 rhubarb or calomel ; also in sick-headaches, gout and gravel. Dose, 

 gr. X to 3j. The carbonate is given in double the dose. 



