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XXVI. — On Dried Blood as Manure. By J. Thomas Way, 

 Consulting Chemist to the Society. 



The value of blood as manure has been long known, but many circum- 

 stances have combined to prevent it from being employed to any con- 

 siderable extent. 



That blood should be a highly fertilizing substance, we should infer 

 from its composition. I do not propose here to go into any elaborate 

 statement of the analysis of blood, my object being principally to inquire 

 what prospect there is that this valuable substance may be rescued from 

 waste, and systematically thrown into the manure market as a dry and 

 portable manure. But it may be as well to state that ox-blood, according 

 to the analysis of Dr. Playfair, contains from 79 to 82 parts of water, the 

 remaining portion, of from IS to 21 parts, being, of course, dry matter. 

 In this respect blood very closely resembles flesh, which, according to the 

 same authority, contains 77 parts of water and 23 of dry matter. The 

 ultimate composition of blood and flesh is identical. Omitting the ashes 

 in each case, Dr. Playfair obtained from the analysis of dry blood and 

 dry flesh the following results : — 



Dry Ox-blood. Dry Ox-flesh. 



Carbon . . . .54*35 54*12 



Hydrogen . . . 7*50 7*89 



Nitrogen . . .15*76 15*67 



Oxygen .... 22*39 22*32 



100-00 100*00 



The proportion of ash in blood is small, not exceeding 5 per cent, on 

 the dry matter. Of this small quantity too fully one-half is common salt; 

 ■whilst perhaps not more than 20 per cent, of the ash is of any great value 

 to vegetation. 



I am inclined, therefore, in speaking of the value of blood as manure, 

 to put aside the mineral matters as too insignificant to require attention, 

 resting its chief merits upon the fact that it is almost pure animal matter, 

 and contains a high per centage of nitrogen. Hitherto comparatively 

 little blood has been prepared in the dry state, and that little has been 

 sold to the makers of prussiate of potash. Some manufacturers, however, 

 are now turning their attention to the possibility of preparing the dried 

 substance on a large scale for manure, and 1 am in hopes that the value 

 of this substance will be found such as to enable farmers to purchase it at 

 a price high enough both to remunerate and encourage the maker and to 

 secure its application to the purposes of agriculture. From a manu- 

 facturer of dry blood I have received from time to time several specimens 

 for analysis, and the results are such as to convince me that blood may be 

 dried on the large scale with perfect success ; and that the product ob- 

 tained may fully come up practically to what might be expected from a 

 knowledge of the composition of the material employed. 



The quantity of nitrogen in any specimen of dried blood will be de- 

 pendent principally on two circumstances : first, the extent to which the 

 blood is dried — because, although sufficiently dry to be portable and pul- 

 verulent, it will never be absolutely free from moisture ; and secondly, the 

 care and attention bestowed on the evaporation. It is plain that if the 

 blood get carbonized and burnt its value must be proportionately reduced, 

 and, for this reason, open fires should, if possible, be entirely avoided in 

 the heating operations, and steam-cased vessels substituted. 



