1'LAN <>F KXl'KHl.MKNT. 31 



ral)l)its had lived for several weeks on these diets, it was planned to 

 kill them and to examine their bodies in minutest detail 1'or various 

 eombinations of nitrogen and phosphorus. The same procedure 

 wa> to he carried out in the case of the four female rabbits, and in 

 addition, normal rabbits were to be examined as controls, Unfortu- 

 nately, it proved impossible to obtain young rabbits under these 

 abnormal conditions, that is, living in closely confined quarters 

 :iid fed on an artificial diet. 



The work was begun early in November, 1 ( .M)7, and concluded 

 the middle of March, 1 ( .)()S. Complete nitrogen" and phosphorus 

 balancc> \\ere determined during a period of nearly live months. 

 Moreover, the inorganic phosphorus \\as estimated in the urine by 

 the uranium acetate method throughout the entire time. In addition, 

 during the last four \\eek>, calcium, magnesium, and ether-alcohol 

 soluble phosph. thin) balances were included to make the 



study of the phosphorus metabolism more complete. 



At the end of the period the rabbits were chloroformed, and the 

 bones, tc.-th, blood, liver*, nervo (including the spinal cord) and 

 hraii analw.ed for n total phosphoric a< id, lecithin- 



phosphoric acid, calciuii, i, and ether extract. 



Two normal female rabb; : ined and the same procedure 



followed Bfl in the ca>e of the rabbits art ilicially fed. In all cases 

 pos|-morlciii examinat ions \\eie made and slides of t he various tissues 

 were prepared all<l hi>t logical changes n..te<|. 



PREPARATION OF FOOD. 



The food iiTots, gluten, a mixture of starch and 



live oil, ami -lutioii. The above constituents seemed 



to furnish a \\ell-rouiule.l ration, -Mipplying suilieieMt protein, fat, 

 and carbohydrate for the needs of the body. The rabbits to which 

 the ilioriranic phosphorus salts \\ere fed received daily 5 CC of a 

 standard >alt mixture ron>i>ting of {."in grains of sugar, 4 grams of 

 calcium chlorid, ! .", Drains of .sodium chlorid, 1*0 grains of potassium 

 chlorid. and < MUIU sulphate, made up to a volume of 



1 CC and containing ' phosphoric acid, in the form 



ot di-Midium hydrogen j)hosphate and sodium dihydrogen phosphate, 

 per cubic centiiiH 



The rabbits to which the organic phosphorus was fed received daily 



of a salt mixture made >o as to supply an e(|uivalent amount of 



the above mineral salts, allowance being made for the presence of 



calcium, magnesium, potassium, and phosphorus in the phytin. In 



this way an equal amount of calcium, magnesium, potassium, and 



1 th nitrogen work was done by th- niiro^-ii laboratory, Mr. T. C. Trescot in 

 char 



