MINERAL METABOLISM 335 



the increased acidity was not accompanied by an increase in urinary 

 phosphorus. 



The administration of alkalies to man depresses urinary ammonia and 

 tho urine may be made alkaline like that of herbivora (Janney(a) Hender- 

 son and Palmer) ; the complete suppression of ammonia cannot be secured 

 in normal subjects though it is possible in nephritis (Denis and Minot(6 ) ). 

 The benefit resulting from the giving of alkali in a number of pathological 

 conditions in which acidosis exists, such as diabetes, infantile diarrhea 

 (Howland and Marriott), cholera (Rogers), is temporary and the value 

 of the practice is questioned, but a critical loss of alkali from the blood and 

 tissues is thereby prevented. The acidosis of nephritis (Palmer and Hen- 

 derson ) accompanied by decreased NIL, excretion is a result not of over- 

 production but of kidney insufficiency and a consequent retention of acid 

 phosphate; this may even be increased by giving sodium bicarbonate. 

 For this reason the value of Ca in this condition is emphasized (Marriott 

 and Rowland (a)) because Ca leaves the body largely by way of the intes- 

 tine ; the value of lime in correcting the acidosis of diabetes has also been 

 indicated (Kahn and Kahii(a)). The influence of alkalies on the course 

 of sugar utilization and on lactic acid formation v and the effects of acids on 

 nitrogen metabolism, may be cited as further instances out of many others 

 indicating a regulation of the processes of metabolism by the alkaline re- 

 serve of the blood and tissues ( Underbill (i) ; Murlin and Graver; MacLeod 

 and Fulk; McCollum and . Hoagland () ; Steenbock, Nelson and Hart). 



The important role of ionic substances in life processes, in the be- 

 havior of the individual cell and in the activity of various isolated tissues, 

 such as nerves, muscles, and especially the heart, need not be considered 

 in a discussion of the metabolism of mineral matter. For normal dis- 

 charge of its functions every tissue seems to require a properly balanced 

 adjustment of ions in its fluids and membranes and the source of these 

 mineral substances is the ingested food; but to what extent the processes 

 involving ion interactions consume tho minerals involved and thereby re- 

 quire their constant renewal in the food, and where the accumulated body 

 reserves are stored, and by what mechanism the physiologically proper pro- 

 portions of the various ions are selected by the tissues from the hetero- 

 geneous supply brought to them by the blood and lymph, are unanswered 

 questions. The tetany following parathyroidectomy may be an example 

 of the unbalancing of ionic equilibrium necessary for normal muscular or 

 nervous activity. Decreased blood calcium accompanies the tetany and 

 administration of calcium relieves it ; but the calcium reserves of bone seem 

 not to be available for this purpose. To calcium has been ascribed a very 

 important role in correcting almost all kinds of disturbances in inorganic 

 equilibrium, but the translation of inorganic equilibrium into the language 

 of inorganic metabolism must await more knowledge of the terms under 

 which the processes of each are carried on. 



