in its Relations to Physiology. 417 



rial blood passes through the kidneys and venous blood through the 

 liver, and all this proves to him that the author has not sufficiently 

 studied the principles of the science upon which he writes.* 



Even admitting that these views are grossly erroneous, was their 

 establishment the object of the author's labours ? When he endeavoured 

 to ascertain the composition of bile, of urea, of uric acid, of blood, and 

 the organic tissues, and to discover their relations to the aliments and 

 secretions, was it not perfectly indifferent, as far as his immediate 

 object was concerned, whether the urine is secreted from venous or 

 from arterial blood ? and whether the heart is a force and suction-pump, 

 or not? 



When the chemist maintains that the blood is not formed from 

 starch and sugar ; that the bile is not to be found in the faeces, but is 

 eliminated from the organism in a gaseous form ; when he develops his 

 theories that those remedies, which are products of organic life, take a 

 share in the processes in the animal organism, similar to that which we 

 positively know is taken by all the vegetable nutritive matters ; when 

 he further asserts that uric acid and urea are products of the transmu- 

 tation of matter, and are not directly derived from the aliments ; when 

 he points out a close connection between nutriment, loss of heat, and 

 consumption of energy ; ought all these assertions, after the labours 

 which have preceded them, and whereon they are founded, to be styled 

 11 probability-theories," " fantastic notions ?" must all the investigations 

 made during the last thirty years be deemed to have produced no re- 

 sult whatever capable of any useful application ? 



Must I, then, remind my opponents what notions prevailed, even so 

 late as four years ago, on the nutrition of plants ? Must I remind them 

 of the fact, that the result of the last investigations of Boussingault, 

 with regard to the advantages of the rotation of crops, consisted in his 

 ascribing them to the destruction of weeds, and that the cereals receive 

 their nitrogen from the manure, whilst the leguminous plants derive 

 part of it from the atmosphere? How many proofs of the correctness of 

 the principles laid down by me, could I not place in Berzelius' hands, 

 obtained from the most intelligent, the most clear-headed farmers of 

 England and Germany, who have had occasion to test and verify their 

 correctness, in a simpler and safer method of cultivation — an infinite 



* " Thus we have seen it stated in chemico-physiological works that the heart is a pressure 

 as well as a suction-pump ; that the urine is secreted from venous blood ; that arterial blood, 

 before it returns to the lungs, passes through the kidneys, whilst venous blood passes through 

 the liver, &c. This proves sufficiently that the author had not thoroughly studied the principles 

 of the science on which he wrote."— (Berzelius,Twcnty-third Annual Report, p. 573.) 



