CHI.MK AI. ANALYSTS OF RABBITS. 53 



BRAINS. 



The brains of the rabbits were completely removed and dried in 

 platinum dishes, then ground in a mortar and mixed as well as pos- 

 sible before analyzing. The a>h v.iried from 7.0 to 7.82 per cent, 

 being highest in the normal brains. As the age and other factors in- 

 fluence the asli content of all organs, this variation h.as no significance. 

 The percentage of calcium shows some variation and is likewise high- 

 est in the ash of the brains of the normal rabbits. 



The percentage of magnesium remains fairly constant in all cases. 

 The ratio of calcium to magnesium in the brains is 6.3: 1 in the normal 

 rabbits. \.~>:\ in the brains of those fed inorganic- phosphorus, and 

 3.5:1 in the brains of those led organic phosphorus. 



The total phosphorus found in the brains is about the same in all 

 CaaeS, but this i> not true of the ether-alcohol soluble phosphorus. 

 The brains of the rabbit-; fed organic phosphorus show 2.35 percent 

 ]>ho>|)horus afl ether-alcohol soluble,' or ").).: 1-1 per cent of the total. 

 The brains of tlio-<- fed inorganic phosphorus show but 1.16 percent 

 pho>phorus as et her-alcohol soluble phosphorus, or LN..")1 per cent of 

 the ttal. This j. louer than the figures for brains of the normal rab- 

 bi is. which contain U.07 per cent of the phosphorus in a form soluble 

 in ether and alcohol. It appears from these figures that the brains of 

 the rabbits fed organic pho>phorus contain an appreciably larger 

 amount of ether-alcohol soluble phosphorus than do the brains of 

 rabbits fed on inorganic phosphorus or those of the normally fed rab- 

 bits. (Table VIII 



\ i i : \ i > 



The ash content on a water-free basis shows a fairly constant 

 percentage in al As in the brain, the calcium content of the 



ncr\rs \s higher for the normal rabbits than in the other 08860. 



The amount of magnesium in the nerves of the normal rabbits is 

 0. U per cent, 0.11 per cent, or practically the same, in the nerves 

 of those fed organic phosphorus, and one-half, or 0.06 per cent in the 

 nerves of those fed inorganic ph,phoru-. 



The ratio of the calcium to the magnesium is much lower in the 

 nerve< of the rabbits fed organic phosphorus than in the other cases. 

 The data for ether-soluble material are fairly uniform, being a trifle 

 lower for the nerves of the normal rabbits than for the experimental 

 rabbits. 



The total phosphorus content varies from 3.72 per cent in the case 

 of the rabbits fed organic phosphorus to 4.28 per cent in the case of 

 those fed inorganic phosphorus. The amount of ether-alcohol soluble 

 phosphorus is lowest in the case of the rabbits fed on inorganic 

 phosphorus, the percentage of the total phosphorus in this form being 



