SACCHARUM LACTIS 447 



CONSTITUENTS. A large percentage (about 87 per cent.) of milk is repre- 

 sented by water, 4 per cent, by butter, 5 per cent, by sugar and soluble 

 salts, and only about 3.6 per cent, by casein and insoluble salts. 



Butter is composed of olein (about 30 per cent.), palmitin, and stearin 

 (68 per cent.), and about 2 per cent, of glycerides of butyric and other acids. 



Casein, which is soluble in a solution of the alkalies, is a modification of 

 albumen, and is precipitated from solution by the action of rennet or acetic acid. 



Lactic acid (Acidum Lacticum, U.S.), which is developed by the action 

 of heat, is said not to be a normal constituent of milk, but is always present 

 in sour milk. Syrupus Calcii Lactophosphatis employs this acid. Dose: 

 8 mils (2 fl. dr.). 

 PREPARATION: LAC FERMENTATUM, N.F. 



623 a. SACCHARUM LACTIS. SUGAR OF MILK. LACTOSE. Forms about 5 

 per cent, of milk and is obtained from the whey by evaporation and recrys- 

 tallization. A hard, somewhat gritty, slightly sweet powder, almost in- 

 odorous. Soluble in about six parts of water. For Tests see U.S.P. It 

 has been recommended as a dietetic in wasting diseases, but in pharmacy 

 is merely a diluent for triturations of various kinds. 



ACTION AND USES. Milk is nutritious, and its value as an article of diet 

 is well known. In addition to this use, milk may be satisfactorily em- 

 ployed as a vehicle for the administration of certain remedies having an 

 unpleasant taste. 



624. OS. BONE. 



SOURCE. The skeleton of vertebrate animals. 



CONSTITUENTS. Calcium phosphate 40 to 67 per cent., which includes a 

 small percentage of calcium carbonate; phosphates of magnesium and other 

 salts are also present. With the salts are also found organic substances yield- 

 ing gelatine on boiling with water. The basic substance of the bony struc- 

 ture contains two chief constituents, namely, an organic substance, ossein, and 

 the so-called bone earth inclosed in or combined with it. Ossein is generally 

 considered identical with collagin of the connective tissue. 



Preparation of Ossein: that portion of bone that is left undissolved after treat- 

 ment with HC1. 



USES. For preparing bone-black, animal charcoal, and phosphates. 



625. GELATINUM (U.S.). GELATIN. 



SOURCE. Bone, cartilage, skin, tendons, and ligaments; a boiling-hot 

 solution of these, resulting in a jelly when cooled, is dried in the air. 



DESCRIPTION. Thin, transparent sheets or porous, opaque layers or shreds, 

 amorphous, swelling in water without dissolving, dissolving in warm' water, 

 forming a sticky liquid which solidifies on cooling. The solution is laevo- 

 gyrate. Solutions of gelatin on boiling are not precipitated either by mineral 

 acids, acetic acid, alum, lead acetate, or mineral salts in general, but precipi- 

 tated by potassium ferrocyanide, tannic acid, mercuric chloride in the presence 

 of HC1 and NaCl, and by alcohol, especially when neutral salts are present. 

 Its solution containing KCrzOr yields an insoluble compound on exposure to 

 light. 



Gelatinoids. To this group belong a number of substances occurring in 

 bones, skins, horns, etc., having generally the property of forming a jelly 

 with water. The organic matter in bones, usually called ossein, contains, 

 besides albuminous substances, the two gelatinoids, collagin and gelatin, a 

 pure mixture of which forms common glue. Chondrin resembles gelatin; 

 it is obtained from cartilages of the ribs and non-ossifying cartilages; its 

 aqueous solution is precipitated by alum, lead acetate, ferric salts, acetic 

 acid, and a small quantity of mineral acid, but not precipitated by tannin or 

 mercuric chloride. Properties: Emollient, nutritive, and protective. 



626. SEVUM SUET 

 . MUTTON SUET 



The internal fat of the abdomen of O'vis a'ries (Fam. Bovidas), purified by melt- 

 ing and straining. Suet should be kept in well-closed vessels impervious to 

 fat. It should not be used after it has become rancid. 



