14 CHEMISTRY AND PHYSICS IN RELATION 



quiry. A new expression for catarrh, as arising from some active injury to the 

 cutaneous nerves, is no actual again, but a mere ideal representation. 



EXEECISE OF THE IMAGINATION WITH REFERENCE 

 TO OBSERVATION. 



The right use of our senses as in the appreciation of the distance, or height, 

 or circumference of a body is acquired by experience and reflection, and so also 

 is the right conception of a natural phenomenon ; and the reflection of it in all 

 its purity, undimmed by the representations awakened during our perception of it, 

 is the attribute of a well trained mind. The botanist recognizes at a glance the ex- 

 istence, and the varieties of the plants around him : the painter sees a multitude of 

 points which the unskilled eye cannot detect even after the most fixed attention. 

 None of the experimental sciences demand this acuteness and exercise of the 

 imaginative faculty more strongly than physiology and pathology ; and in few is 

 it more rarely met with than in medicine. Hence arise the many contradictions 

 in the comprehension of the Amplest conditions, and the close succession of the 

 most opposite modes of cure, and the constant appearance and speedily forgotten 

 existence of numerous works on the unhealthiness of certain localities, on the 

 nature of yellow fever, cholera, and the plague works that have often been written 

 by men, who never saw the place they describe, or a single case of any of the 

 diseases they profess to treat of. In order to give validity to a theoretic view of 

 chemistry and physics, it is indispensable that its truth be guaranteed by a series 

 of practical investigations on the part of the writer. If this be wanting, the theory, 

 although it may be the perfectly correct expression of a truth, will meet with little 

 or no attention. It required the keen imaginative faculty of a Berzelius to save 

 from utter disregard such a theory as that advanced by Richter* on chemical pro- 

 portions, and to recognize the innate truth and existence of a common law of com- 

 binations amid a mass of false facts ; among which, that single one, which forms 

 the starting point for the table of equivalents the nonexisting carbonate of alumina 

 was sufficient to destroy all faith in the others. 



ERROR ORIGINATES IN FALSE OBSERVATIONS AND COMBINATIONS. 



Viewed with reference to natural inquiry, every erroneous mode of investigation 

 depends upon the want of just observations, and the false conceptions we deduce 

 from them ; and is further based upon the error of considering the simultaneous 

 occurrence, and concurrence of two phenomena as the proof of the existence of a 

 connection between them. In nature numerous phenomena occur, of which one 

 may be inappreciable, if another given one fail, while again innumerable other 

 phenomena may occur together, or simultaneously, without standing in any mutual 

 relation to each other. The assumption of an erroneous connection of this kind, 

 originates in all cases in a false mode of investigation ; and thus the combination of 

 two phenomena, only similar in some one particular relation, is always the result 

 of incorrect observation. 



* Richter's work entitled. " Anfangsgriinde der Stochyometrie, oder MessJcunst chy- 

 mischer Elemenle." (Elements of Stochyometry, or the Mathematics of the Chemical 

 Elements,) was published in 1792. Its object was a rigid analysis of the different salts, 

 founded on the fact that when two salts decompose each other, the salts newly formed 

 are neutral as well as those which have been decomposed. He endeavored to de- 

 termine the capacity of saturation of each acid and base, and to attach numbers to 

 each, indicating the weights which mutually saturate each other. 



