4 ESSENTIALS OF CHEMICAL PHYSIOLOGY 



formed by putrefaction in the alimentary canal. With some few ex- 

 ceptions such as these, the elements enumerated above are found 

 combined with one another to form compounds. 



The compounds, or, as they are often termed in physiology, the 

 proximate principles, found in the body are divided into 



(1) Mineral or inorganic compounds. 



(2) Organic compounds, or compounds of carbon. 



A convenient practical method of grouping these proximate 

 principles of the body and of food is the following : 



(' Water. 



Inorganic .... Salts e.g. chlorides and phosphates of sodium 



( and calcium. 



| Proteins e.g. albumin, myosin, gelatin. 

 Nitrogenous ' Simpler nitrogenous bodies e.g. lecithin, 

 creatine, urea. 



Organic 



(Fats e.g. butter, fats of adipose tissue. 

 Carbohydrates e.g sugar, starch. 

 Simple organic bodies -e.g. alcohol, chole- 

 sterin, vegetable acids and salts, lactic acid. 



Many of the substances enumerated above only occur in small 

 quantities. The most important are the inorganic substances, water 

 and salts ; and the organic substances, proteins, carbohydrates, and 

 fats. It is necessary in our subsequent study of the principles of 

 chemical physiology that we should always keep in mind this simple 

 classification ; the subdivision of organic substances into proteins, 

 fats, and carbohydrates forms the starting point, the A B C, as one 

 might say, of chemical physiology. 



I shall conclude this introductory chapter by giving a list of the 

 apparatus and reagents necessary for a practical study of the subject, 

 and some tables to which it will be often found convenient to refer. 



The following set of reagents conveniently contained in 4 to 6 oz. glass 

 stoppered bottles should be provided for each two students : 



Sulphuric acid, concentrated. 

 25 per cent. 



,, ,, O'l per cent. 



Nitric acid, concentrated. 

 Fuming nitric acid. 

 Hydrochloric acid, concentrated. 

 0-2 per cent. 1 

 Acetic acid, glacial. 

 20 per cent. 







Glyoxylic acid. 

 Formaldehyde. 



1 Made by adding 994 c.c. of water to 6 c.c. of the concentrated hydrochloric 

 acid of the British Pharmacopoeia. 



