800 



Animal Offals. 



Vol. XI. 



useful, especially to present the blood in a 

 suitable state of division, and to render its 

 decomposition slower and more regular. We 

 can know, moreover, what surface these 

 mixtures will cover as manure, by recollect- 

 ing that three thousand pounds of liquid 

 blood give seven hundred and fifty pounds 

 of blood coagulated and dried, which is suffi- 

 cient to manure an acre. One hundred 

 pounds of blood in this state, equal as a ma- 

 nure three hundred pounds of broken bones, 

 or three loads of good horse-dung, weighing 

 together seven thousand and two hundred 

 pounds. It is a manure by far superior to 

 those known and designated by the names 

 of poudrette, oil cakes, &c. ; it is inferior 

 only to the dried and powdered flesh. 



Of the entrails, ^fc. — All the internal 

 parts of animals, such as the liver, lungs, 

 brain, heart, and the offal of the entrails, 

 should be cut or hashed as fine as possible, 

 and then mixed along with the emptyings 

 of the intestines, with earth thoroughly dried, 

 the latter in the proportion of six times the 

 bulk of the animal matters. When this 

 composition has been well worked over with 

 the shovel, it is spread at the rate of five tons 

 to the acre. 



This manure gives excellent results, and 

 is particularly favourable to wheat crops. If 

 it cannot be spread immediately after its 

 preparation, it must be preserved in a trench 

 or some other cool place, or at any rate in 

 the shade and covered with earth. 



Bones: explanation of the various results 

 of their use in agriculture. — None of the 

 hard substances, the remains of animal or- 

 ganization, offer more remarkable examples 

 of various effects in its action as a manure, 

 than the bones in different states. We find 

 in the numerous agricultural memoirs on the 

 subject, the most singular problems which 

 practice could leave to be solved. 



The bones which are found in masses of 

 any considerable importance at the disposal 

 of agriculturists and speculators, are pre- 

 sented in the following different forms: 

 Fresh, such as have been taken from ani- 

 mals recently slaughtered, more or less 

 broken, or whole: in each of these three 

 states, their decomposition is almost always 

 too slow, stimulated though it be by the well 

 known influences of air, heat and moisture ; 

 but, all things being equal externally, enor- 

 mous differences have been observed, and 

 which seemed inexplicable, in the duration 

 of the decomposition, and consequently in 

 the useful effect produced in a given time. 



Some particular experiments have led me 

 to discover the cause of these apparent ano- 

 malies. Bones contain in their cellular parts 

 and in various cavities, a fat substance, se- 



creted by itself, of more or less consistence. 

 This substance is free in the adipose tissue 

 of all the crevices which conceal it, for it 

 suffices to open a passage for it by cutting 

 the bones and plunging them in hot water, 

 to bring it out and see it swimming upon the 

 surface of the liquid. The average propor- 

 tion which can be obtained from the various 

 bones of the butcher, is about .01, although 

 the very spongy parts which enclose the 

 most, contain even ,05. 



The proportion of fat matter extracted by 

 this process, diminishes gradually as the 

 bones are dried; it becomes almost nothing 

 when the desiccation takes place at a high 

 temperature, either in the sun or by a stove. 

 It appears, indeed, that as fast as the water 

 which filled the interstices of the bone has 

 evaporated, the grease liquefied by the heat 

 has taken its place. One of the effects of 

 this penetration, has been to impregnate the 

 net-work which encloses the phosphate and 

 the carbonate of lime. This net-work al- 

 ready with difficulty decomposed on account 

 of its cohesion and insolubility, protected 

 moreover by inorganic substances interposed, 

 becomes still less alterable when the greasy 

 matter not only impregnates and defends it 

 from the penetration of water, but, becoming 

 gradually acidified, forms with the lime a 

 calcareous soap, which M. d'Arcet has shown 

 to be undecomposable under atmospheric in- 

 fluence. 



Bones in this nearly undecomposable state 

 should, of course, exert but an insensible ac- 

 tion as a manure, at least, unless very mi- 

 nutely divided. This also confirms and ex- 

 plains the practical remark, that although 

 spread upon the ground for four years, these 

 bones scarcely lost 0.08 of their weight, 

 while, when recently taken from animals 

 and deprived of nearly all their grease by 

 boiling water, they readily permit the de- 

 composition of their organic net-work, and 

 lose in the same time from twenty-five to 

 thirty per cent, of their weight. 



Let us notice three other curious and ap- 

 parently singular results of the use of bones 

 treated with steam. 



The broken bones from which gelatine has 

 been obtained by the action of water and 

 heat, in various processes, form a residuum 

 which has often been tried as a manure. In 

 some experiments a number of cultivators 

 have obtained from these residuums, the first 

 year, more beneficial effects than from bones 

 themselves. In others, an action almost equal 

 to that of bones, but less durable, was ob- 

 served. More generally, however, little or 

 no favourable influence upon vegetation was 

 obtained. A great number of analyses, at- 

 tentively examined, have enabled me to per- 



