1864.] CHEMISTRY OF MANURES. 205 



likely to incre tse the relative demand for ammonia ; especially as 

 poor lands, of naturally low aramoniferous endowments, will proba- 

 bly be those selected I so far as local • ircurastances permit) for 

 irrigation with town sewage. For, though sewage is rich, as well 

 in the nitrogenous as in the cinereal constituents of the food con- 

 sumed in towns, it is not proportionately so rich in tlic former as 

 in the latter ingredients ; the reason being that part of the ammo- 

 nia of food is dissipated during the processes of animal life,* 

 wherea> all the fixed cinereal constituents that are taken into the 

 system of adults reappear undiminished in their ejecta. Moreover, 

 no waste necessarily attends the transit of the cinereals in solution, 

 along the subterranean conduits, from the houses in which they 

 are produced to the fields in which they are consumed ; whereas 

 the ammonia of sewage is liable to undergo a considerable amount 

 of waste during its passage from town to country in the ordinary 

 conduits ; a circumstance which (it may be parenthetically men- 

 tioned i has led 3Ir. F. 0. Ward to the belief that, in the future 

 progress of urbui organization, it will be found economical to pro- 

 vide separate urinary and faecal systems; bringing thus, by a fur- 

 ther refinement, the collective organism into closer correspondence 

 with the individual. The probability of this ulterior improvement 

 will, perhaps, be the more readily recognized, when it is considered 

 that three fourths and upwards of the value of human tj eta are 

 comprised in the urine, — only the fractional remainder in the leeces. 

 But, as even tlie separation of sewage from rainfaii is not yet 

 officially admitted, it would be a premature and therefore a hope- 

 less crusade to press, at present, for further niceties vi organiza- 

 tion. These will come in due time, when the residua of towns, 

 now officially described as '* a nuisance to be got rid of,"" shall be 

 regarded in their just light as " a property to be administered," 

 — nay more, as the property on whose sound administration depends, 

 in a greater degree than on any other single condition, the lasting 

 prosperity of nations. 



Reverting to the nitrogen question, should it prove true that a 

 dissipation of ammonia takes place, as some experimentalists main- 

 tain, during the growth of cereal plants; and shouid this waste 



* This point has been made the subject of direct experitn»iut3 bj 

 Boussingault, Barral, Regnault, Reiset, and Lawes, and iiima^y- be laiien 

 as a fair averaj^e estimate, that, of the nitrogen coudumtd in the food, 

 only about four iif;hd are recoverable in the ejecta. 



