444 coMPOsncN of blood, and of skin. 



Wafer. Dry animal malfer 



Muscular fibre 77 23 



Blood .79 21* 



It appears singular that the solid muscle of animals should contain 

 so nearly the same quantity of water as their liquid blood does. 



But it is no less striking that the dry animal matter which remains, 

 when lean muscular fibre and when blood are fully dried, has nearly the 

 same apparent composition. Thus, according to the analyses of Play- 

 fair and Boeckman, dry flesh and dry blood consist respectively of— 



Dry be*^ Dry ox blood. 



Carbon 51-83 51-96 



Hydrogen 7-57 7-25 



Nitrogen 15-01 15-07 



Oxygen 21-37 21-30 



Ashes 4-23 4-42 



100 loot 



The org-amc part, therefore, of blood and of flesh is nearly identical 

 in ultimate composition, and the final result of equal weights of each, 

 when applied as manures, should be nearly the same. The ashes, how- 

 ever, or inorganic part, though present in each nearly in the same pro- 

 portion (4-23 and 4-42 per cent), are somewhat different in composition, 

 and therefore the action of blood and flesh will be a little unlike in so 

 far as it depends upon the saline substances they are respectively capa- 

 ble of conveying to the roots of plants. 



3°. Skin. — The skins of nearly all animals find their way ultimately 

 into the soil as manure, in a more or less changed state. 



The refuse parings from the tan-yards, and from the curriers' shops, 

 though usually employed for the manufacture of glue, are sometimes 

 used as a manure, and with great advantage. They may either be 

 ploughed in sufficiently deep to prevent the escape of volatile matter 

 when they begin to decay, or they may be made into a compost by 

 which their entire virtues will be more effectually retained. 



Skin differs considerably in its constitution from flesh and blood. It 

 contains, in the recent state, about 58 per cent, of water, and leaves, 

 when burned, only 1 per cent, of ash. The combustible or organic part 

 consists of — 



Carbon 50-99 



Hydrogen 7-07 



Nitrogen 18-72 



Oxygen 23-22 



100 

 It contains, therefore, 3* per cent, more nitrogen than flesh or blood. 

 So far as the fertilizing action of these substances depends upon the 

 proportion of this constituent — glue, the parings of skins, and all gelati- 

 nous substances, will consequently exhibit a greater efficacy than flesh 

 or blood. 



* Thomson's Animal Chemistry, pp. 285 and 367. 



T Liebig's Organic Chemistry applied to Physiology, p. 314. 



