into the Practices and Results of Hoi^ticidttire. 401 



applied, and under certain circumstances, it is capable of pro- 

 ducing the most beneficial effects ; I believe it will be found 

 that it is not the most efficient that is produced by fire ; nor 

 that which acts with the greatest facility, in imparting to inert 

 carbonaceous matter the active principles of fertility. 



With a view to discover this, and thereby the means of 

 preparing a substance that may be dissolved in water, and thus 

 be capable of supplying plants with the requisite nourishment, 

 without awaiting the result of the usual process of natural 

 decomposition by the putrefactive fermentation, or of being 

 under the necessity of stirring up the earth, or, when in pots, 

 of changing the soil, and thus disturbing the roots, I made a 

 great number of experiments ; and the substance which I found 

 to be the most efficient in every respect, in imparting those 

 principles to the soil, which is requisite to sustain plants in 

 health and vigour, was the serum, or watery part of blood, 

 which separates from the clotted part, or crassamentum, after 

 it has been a few days taken from an animal. This substance, 

 diluted with five or six times its quantity of water, and applied, 

 by pouring a suflficient quantity on the surface of the soil, to 

 saturate the earth to the depth of the roots, enabled plants of 

 every description that we are in the habit of cultivating, when 

 planted in a soil perfectly destitute of carbonaceous matter, to 

 attain the utmost size to which I had ever seen them grow in 

 the most luxuriant soil ; and such plants were thus brought to 

 fructify at a much earlier period, and with greater vigour, than 

 by any other means, or supply of food. The solid, or clotted 

 part of the blood could not be made available, until reduced 

 by decomposition ; and as the putrefactive fermentation was 

 unavoidably attended with obnoxious effluvia, I at first re- 

 duced it by lime, but although thus rendered soluble, and 

 productive of fertility, it was not so much so as the serum. 

 Desirous of ascertaining what peculiar principle was contained 

 in the serum that was not in the crassamentum, and what 

 created the difference in those substances, I prevailed on an 

 eminent chemist to analyse the blood of an ox, and the result 

 was as follows : — 



The serum contained The crassamentum contained 



Water - 5620 parts 



Albumen - 1400 

 Fibrine - 2400 



Colouring matter 580 



Water 



8784 parts 



Albumen 



980 



Alkaline salts 



256 



in every 10,000 



in every 10,000 



The difference, then, in these two substances appears to be 

 that the crassamentum contains no alkaline salts, and the serum 

 Vol. V. — No. 21. d d 



