10 On the Composition of tJie 



one-half more of flesh-forming constituents than the other por- 

 tions of the roots, as will be seen from the following determina- 

 tions : 



Layers between 



In outer Layers. Heart, the Heart and the 

 outer Layers. 



Percentage of nitrogen . . 1-039 T067 1-500 



equal to 

 Protein compounds . . . 6'493 6'668 9-375 



It is worthy of notice, that the albuminous or protein com- 

 pounds are not uniformly distributed throughout the whole mass 

 of the root. I have not examined any other root in this respect ; 

 but, judging from analogy, we may expect to find a similar dis- 

 tribution in other kinds of roots. 



In ascertaining the nutritive value of roots, which is now 

 usually done by the indirect method of combustion, care must be 

 taken to obtain for analysis a fair average sample of the whole 

 root, for the nutritive value of the root will either be stated too 

 high or too low if the portions analysed contain more of the 

 exterior or the intermediate portions of the root, as actually 

 contained in the whole root. For this reason I find it advisable 

 to prepare the sample of the root to be used for combustion, by 

 cutting the whole root into slices, which, on being dried, are 

 powdered together. A fair average sample of the whole part is 

 thus obtained for analysis, and all errors, arising from the want 

 of uniformity of distribution of the albuminous matters in root- 

 crops, are thereby avoided. 



II. Composition oj the White Belgian Carrot. 



a. Carrots grown in 1851. 



Water. 1. Dried in the water-bath fresh carrots lost 88'06 

 per cent, of water. 



2. In a second determination 88'47 per cent, of water were 

 found. On an average carrots thus contain 88 26 per cent, of 

 water. 



Ash. 1. 100 parts of fresh carrots were found to contain 0'74 

 per cent, of ash. In the dried state, accordingly, they contain 

 6'22 per cent, of ash. 



2. In a second determination the percentage of ash in fresh car- 

 rots was ascertained to be 0'75, or in dried roots 6'56. On an ave- 

 rage fresh carrots thus contain 0'74 per cent., and in the dried 

 state 6*29 per cent, of ash. 



Protein Compounds. 12'81 grains of dry carrots burned with 

 soda-lime gave 1*66 grains of chloride of platinum and ammo- 

 nium. 100 parts of fresh carrots accordingly contained 0'095 of 

 nitrogen equal to 0*596 of protein compounds; and in the dried 



