54 METABOLISM OF ORGANIC AND INORGANIC PHOSPHORUS. 



34.25 per cent against 64.26 per cent in the case of the rabbits fed 

 on organic phosphorus, and 59.23 per cent in the normal rabbits. 

 These results are similar to those recorded in the case of the brains. 

 (Table VIII.) 



TEETH. 



The teeth were freed from adhering bone and muscle tissue by 

 scraping and were dried in a hot-air oven at 100 C. The ash was 

 constant in all cases, averaging 75 per cent. There was somewhat 

 more calcium and a trifle less magnesium found in the teeth of the 

 normal rabbits than in the teeth of the phosphorus-fed rabbits. 

 These results run parallel with those obtained for calcium in the case 

 of the bones of the rabbits. The total phosphorus was practically 

 no higher in the normal rabbits than in the other cases. (Table VIII.) 



INTESTINES. 



Phosphorus was estimated in portions of the small intestines of the 

 various rabbits. The loops of intestine were well washed and dried 

 between filter papers and then in an air bath at 45 C. for five hours. 

 When sufficiently dry they were cut into small bits. Moisture and 

 total phosphorus were determined on a weighed quantity of this 

 substance and on another portion the following extractions were made : 



One gram of substance was ground fine with pure sand in a porcelain mortar and 

 transferred to a 300 cc Erlenmeyer flask. Thirty cubic centimeters of absolute ether 

 were then added and the whole extracted on the water bath overnight, using a reflux 

 condenser. The ether extract was then filtered through a hardened filter into an 

 ordinary Jena flat-bottom flask. Particles of residue found on the filter paper were 

 scraped back into the Erlenmeyer flask. To this ether extract residue 60 cc of abso- 

 lute alcohol were added and boiled for three hours, using a reflux condenser. This 

 alcohol extract was filtered hot into the Jena flask containing the ether extract and the 

 residue washed twice with separate portions of 25 cc of hot alcohol and the washings 

 were added to the combined extract. Phosphorus was determined in the combined 

 ether-alcohol filtrate by the Neumann method. 



The ether-alcohol extraction residue was next treated six times with 50 cc portions 

 of cold water saturated with chloroform, allowing ten hours for each extraction, using 

 the same hardened filter paper as before and scraping back the residue from the filter 

 paper into the flask. This solution was evaporated to dryness and the phosphoric 

 acid determined therein by the Neumann method. This is called the phosphorus 

 insoluble in ether and alcohol, but soluble in water. Phosphoric acid was then 

 obtained in the residue by difference and called the phosphorus insoluble in ether, 

 alcohol, and water. 



In all cases a large amount of the phosphorus of the fresh sample 

 was soluble in water, fully 50 per cent being dissolved by this means 

 during the preparation of the sample. The amount of phosphorus 

 insoluble in alcohol, ether, and water was higher in the normal 

 rabbits' intestines than in the other cases. The amount of ether- 

 alcohol soluble phosphorus showed but little variation. 



