Dr Seller on the Nutrition of Plants. 55 



soil without the loss of its organic character, would be so 

 much withdrawn from the original stock of organic matter, 

 provided against the demands of the two living kingdoms of 

 nature during their continuance. Many such substances are 

 designedly destroyed, to a great extent, to furnish com- 

 pounds of cyanogen and ammonia. Other sources of this 

 kind of destruction will readily suggest themselves to every 

 one. I will, therefore, content myself with adding one more, 

 namely, the hourly destruction in the article of paper ; how 

 little of the miles of paper daily manufactured in the United 

 Kingdom returns to the soil undecomposed ! 



Thus, on the hypothesis of organic matter being the sole 

 food of plants, there must have been from these and other 

 sources of transformation an enormous annual diminution 

 of the quantity of organic substances in the soil ever since 

 the commencement of the present system of things ; and it 

 follows irresistibly that the two living kingdoms of nature 

 could endure no longer than while the primitive store should 

 withstand this annual demand upon it. Hence, if the truth 

 of this hypothesis could be established, we should have a 

 principle, the application of which, as soon as some preci- 

 sion can be imparted to the data, would bring out the exact 

 period after which the present system of organic nature must 

 cease to exist. On the conti'ary, if Liebig's idea of the food 

 of plants being exclusively mineral, can be realised, it fol- 

 lows, that, whatever destructive accidents the two kingdoms 

 may be liable to in the course of time, they have, in their 

 own economy, ample provision for an unlimited duration.* 



* Since the above communication was read, the translation of Miil- 

 der's Chemistry of Vegetable and Animal Physiology, from the original 

 Dutch, by Dr Fromberg, has appeared. In this work Mulder predicts 

 the extinction of the animal kingdom after a term of years, owing to the 

 poisonous effect of carbonic acid accumulated faster in the air by an in- 

 crease of animal respiration than it is decomposed by plants. He forgets 

 here, that men and other animals cannot increase faster than the means 

 of sustenance are supplied by the vegetable kingdom, and that, accord- 

 ing to his own views, this vegetable sustenance cannot augment without 

 a corresponding removal of carbonic acid from the atmosphere. The 

 abundance of the crops raised for food must compensate for their small 

 bulk, as compared with tiie pristine forests of the earth's surface ; and. 



