EXPERIMENT STATION BULLETINS. 161 



in the body are chiefly olein, palmitin and stearin. They are supposed to be fluid 

 or semi-fluid in the body, because at the same temperature, outside of the body, 

 they become fluid. The body temperature is 37i/l.° C, whereas these fats in the 

 combination in which they are found in the body become fluid at about 25° C* 

 Tliese three fats melt at different temperatures, thus olein melts at — 5° C, 

 palmitin at -r45° C, and stearin at about +55° C. In the intestines the fat of 

 the food is acted upon by the bile and pancreatic fluids which convert some into 

 soap and more into an emulsion in which conditions it is supposed to be absorbed. 

 Cabbopiydrates. — The carbohydates of the food, like the fats, contain carbon, 

 hydrogen and oxygen only. In the carbohydrates, however, the hydrogen and 

 oxygen have a certain constant ratio to each other. They are found always in 

 the same proportions as in water, that is, two parts of hydrogen to one part of 

 oxygen. Typical examples of carbohydrates are sugar, starch and dextrin. So 

 far as the chemical composition of the carbohydrates is concerned, they could be 

 formed by uniting carbon with water, and it is thought that this may be really 

 what nature does in the leaf of the plant, — which is the laboratory where carbo- 

 hydrates are formed. All the carbohydrates conform to the general formula 

 CHjO. There are several products coming under this head which, in some re- 

 spects, are quite similar and yet are the results of different processes and are in 

 reality quite different products. Among these are starch, dextrose, maltose, lactose, 

 cane, sugar and dextrin. These are all carbohydrates. All have formulae nearly 

 identical, yet in action they are essentially different. They may be changed 

 artificially from one form to another in some cases, and nature seems to be able 

 to so change them quite readily. 



Starch — (C(;H,n05)n has quite a definite structure in the plant — varying slightly 

 in different plants — and quite uniform in physical appearance. It is white, non- 

 crystalline in appearance, and insoluble in water. It is very abundant in vegetable 

 foods, constituting on the average over fifty per cent of the total dry matter. 

 It is therefore a useful animal food. Starch is acted upon in the system by the 

 diastase of the intestines and converted into maltose. By the action of dilute 

 acids it may be converted (hydrolized) into dextrose (glucose) or grape-sugar — 

 a point upon which the glucose industry depends. While starch in the raw 

 state is insoluble in water, when boiled for a considerable time it is rendered 

 soluble. It is supposed that the starch granule is protected by a wall or layer 

 of cellulose which does not yield readily to the action of the diastasic ferments. t 

 Boiling, it is thought, may burst this cellulose layer and set the starch granule 

 free. This view is supported by the fact that it is possible to render starch soluble 

 also by grinding for a long time in a mortar which, likewise, must rupture the 

 cellulose layer. 



Dextrose — (CeHjjO,) or grape sugar is found in nature in fruits and honey. 

 It is a term synonymous in these later days, with glucose. It is thought that 

 before being dissolved in the blood, starches and sugars are changed into dextrose. 

 This may be accomplished by a ferment in the intestines called invertin. Dextrose 

 is not .a product of the action of diastase on starch but is the result of the action 

 of invertin on maltose. It is also the sugar which is present in considerable 

 quantities in the blood and urine of diabetic patients. 



Maltose. — (CijHojOi,') or. malt-sugar is the chief end product of the action of the 

 diastase ferment on starch. In the preparation of beer the maltose is produced by 

 the action of the diastase' on the barley starch which is thus changed into a product 

 (maltose), which by the action of yeast is converted into alcohol. This same 

 action goes on in the intestines except that the process stops with the formation 

 of maltose. 



Lactose — (C,2H2,0,,) or milk-sugar has the same chemical formula as 

 maltose but is" quite a different product. It is not so sweet as the other sugars and 

 appears much like starch. It is soluble, however, in water and is the carbohy- 

 drate found in milk. It is present in milk to the extent of about five per cent, 

 and is the sugar which by its transformation into lactic acid, makes possible the 

 souring of milk. ^ 



Cane Sugar — fCioHojOu) or granulated sugar, is the most important sugar of 

 commerce. It is not'present in cereals in large quantities, but is found in abun- 



^-•-♦Halliburton. 



tSee Halliburton's Text-book of Phys. and Path. Chem. There are differences of opinion on 

 this point, but nothing, of an opposing nature, has been established and this article will adhere 

 to the above opinion. 



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