10 



as much fat had been poured off as was possible, the drying was con- 

 tinued in the steam oven until the weight had become approximately 

 constant. As there was still too much fat contained in the samples to 

 permit of their being powdered, it was necessary to extract them with 

 ether before proceeding with the grinding. The extraction with ether 

 was done in the following way. 



Large funnels were placed in hot-water jackets, and in the funnels 

 were placed niters of parchmentized paper. The smooth surface of 

 this paper greatly facilitated the removal of the insoluble residue 

 of the sample. The portion of fat from each sample, which had been 

 poured off as above described, was first passed through this filter and 

 collected in a weighed flask and its weight taken. The remainder of 

 the sample was then treated with ether and brought on to the filter and 

 the washing with ether continued until the fat was sufficiently removed 

 for the sample to be easily pulverized and brought into proper condi- 

 tion for subsequent analytical operations. The ether solution of the 

 fat was also received in a weighed flask. The ether was removed by 

 distillation and the residue heated to constant weight and weighed. 

 There was considerable annoyance from the breaking of the flasks 

 containing the fat while on the steam bath. When there was an evi- 

 dent loss of fat, the fat determinations were recorded as lost. When 

 the flask was discovered with only a slight crack, the results are marked 

 in the following tables with a (?) mark. The portion of the meat on 

 the filter was returned to the dish which had previously contained it, 

 and was again dried to approximately constant weight and then left 

 exposed to the air for at least twenty-four hours in order to establish 

 an equilibrium of its moisture content. The weight of the sample was 

 then taken and recorded as the air dry weight of the material. 



The difference obtained by subtracting the sum of the weights of 

 the air-dry material, fat obtained by pouring, and fat obtained by ether 

 extraction from the original weight of the sample taken was recorded 

 as the weight of water removed in the preparation of the sample. 

 From these data were calculated : 



Percentage of water removed in the preparation of the sample ; 



Percentage of fat removed in the preparation of the sample; and 



Percentage of air-dry sample obtained. 



All three of these were expressed in percentages of the original 

 material. 



The air-dry samples were then ground, so as to pass a sieve having 

 circular perforations 1 millimeter in diameter, and placed in closely 

 stoppered bottles. 



SAMPLES OF SKIN. 



The portions of skin obtained from each cut were united to make one 

 sample of skin for the entire animal. The united sample of skin from 

 each pig was passed through the meat chopper, and the finely divided 

 and thoroughly mixed sample was treated in exactly the same way as 



