42 INORGANIC FOODSTUFFS 



expect them to be from the fact that they are alike diffusible and 

 ionizable very shortly after they arrive within the stomach. 



These considerations have an important bearing upon the practical 

 Question of the modification of cow's milk for infant-feeding. It is 

 me common practice to add lime-water (calcium hydroxide solution) 

 to milk for young infants for two purposes; in the first place in order 

 to delay the acidification and consequent "curdling" of the milk by the 

 hydrochloric acid in the stomach. This results in deferring the floc- 

 culation of the casein until it has undergone partial digestion by the 

 rennin and pepsin in the gastric juice, when the flocculi which are 

 formed are finer and more gelatinous and therefore more easily pene- 

 trable by digestive juices than they are if curdling occurs without pre- 

 liminary digestion. In the second place the lime-water is added with a 

 view to increasing the supply of lime to the infant and thus assisting 

 the growth of bony tissues, teeth, etc. From the latter point of view 

 this practice has been decried in some quarters, on the ground that 

 lime which is not organically combined is not so readily assimilated 

 and utilized as calcium which is in organic combination. We have 

 seen that there is no experimental justification for this distinction, and 

 even if there were, the lime-water which is added to milk immediately 

 combines in considerable proportion with the casein to form a com- 

 pound of exactly the same type, only richer in calcium, as that which is 

 found in normal milk, so that the greater part of the calcium thus 

 administered does in fact reach the stomach in a state of organic 

 combination. 



It is, of course, quite another question whether administration of 

 lime beyond a certain daily amount is of any value in assisting the 

 growth of bony tissues. Experience in connection with other articles 

 of diet conclusively shows us that in many instances the effective 

 administration of foodstuffs is limited by the ability of the tissues to 

 utilize and elaborate them, any supply in excess of this being rejected 

 and wasted. Defective development of bony tissues may be sometimes 

 attributable to deficiency of lime in the diet, but it is probably more 

 often due to inability of the bone-producing tissues to utilize the lime 

 which is presented to them. This, however, obviously constitutes no 

 objection to the addition of lime-water to the milk of an infant; it 

 merely indicates a reason why this procedure by itself may often be 

 insufficient to correct. faulty or deferred development of the calcareous 

 tissues. 



The lime-requirement of the adult is very greatly increased in the 

 female by activity of the mammary glands. Thus from 0.3 to 0.5 

 gramme of calcium oxide per hundred pounds of body-weight per day 

 is sufficient to supply the minimum needs of a pig or goat which is not 

 yielding milk, but a milch-goat requires an additional 1 to 2 grammes 

 of calcium oxide per day for every pound of milk it yields. Insufficiency 

 of lime in the diet under such circumstances results in actual withdrawal 

 of lime from the skeleton, a condition which when it becomes sufficiently 



