402 Necessity and Advantage of Scientific Enquiry 



no fibrine. Hence, concluding that the alkaline salts must 

 be the medium of solution, I added potash, in the proportion 

 of alkaline salt and water contained in the serum, to the cras- 

 samentum, and stirring it occasionally for eight or ten days, 

 I found the greater part dissolved, and then drawing off the 

 liquid part, and applying it in the same manner as I had the 

 serum, it proved to be equally efficient. And as the potassa 

 did not appear so capable of effecting a complete solution of 

 the clot, I added some slaked lime, which answered the pur- 

 pose, and reduced the whole to a state of solution. Having 

 by a variety of experiments with alkaline salts, been led to 

 conclude, that as they imparted no fertility to soils that were 

 destitute of carbonaceous matter, and that this requisite prin- 

 ciple in the food of plants, and contained in the serum, must 

 be furnished by the albumen, I referred to the analysis of this 

 substance, to ascertain the elements of its composition, which 

 are as follows : ■*s»dJo yne a&Ai igoqmoa ;lnoi3rft9 amm a bidfts 



Albumen contains '"'- ''-^ "" "Mbrihe contains, ' " ^'"i}.9V 

 Carbon - S5 parts Carbon - 53^ pacts/ m 



Oxygen ; .>. i.r/^^HjJii oidiije !^^ Pxygen 

 Hydrogen; - . , i^ ., r -Hydrogen - 

 Nitrogen ', '- ■ h^ -"^" «"" ^^trogen - 



'':.(' %■■■ iji Hint every 100 .nilBjIfB aiora n;j.; in .every loo 

 Sih .'{;•-' cQ "TTTti;! (11 uH lici oJ guibio'j^ 



Here we not only have a proof that carbon is the variable 

 substance, and that its absence or presence determines the 

 degree of fertility of the soil ; but we also discover the most 

 efficient principle or agent for rendering it available to plants, 

 and such as appears prepared for the purpose by nature, 

 which is alkaline salt. The alkaline salts have, no doubt, been 

 occasionally noticed as being productiveof fertility, but as their 

 principles of action were either not understood, or not properly 

 defined, their utility has never been established. I have never 

 seen alkaline salts described as necessary, or valuable, ingre- 

 dients in the food of plants, in any chemical work. We know 

 that alkaline salts are the production of vegetables, but, as has 

 been observed, the result of actual experiment proves that al- 

 kaline salts do not impart fertility to the soils that are destitute 

 of carbonaceous matter ; and by the recent experiments of 

 Sir Humphry Davy, it appears that alkaline salts are not, as 

 they were previously considered to be, elementary substances, 

 but compounds, formed of a metallic substance and oxygen ; 

 and that such metallic substance has such an affinity for oxy- 

 gen, that it cannot exist in a separate state in contact with 

 water. Any idea, then, that alkaline salts are reduced to their 

 elements, and thus taken up by plants, must not be entertained. 



It may be difficult to account for the existence of alkaline 



