TO PHYSICS AND PATHOLOGY. H 



minated, at least as far as Germany is concerned. In spite of our acknowledg- 

 ment of the accuracy of the principles of natural investigation, we are but too 

 ready to throw off its shackles, and suffer our unfettered thoughts wherever the 

 way is not clear, to erect a barrier of errors before the gates of knowledge. 

 Favorite antitheses and paraphases still play a chief part in all explanations, 

 robbing common facts and conditions of the simplicity and perspicuity of which 

 they are capable. The deficiency here rests not with the principles, but in the 

 want of their due application. 



EXAMPLES. 



A few extracts from the writings of a distinguished pathologist of the present 

 day will suffice to justify these remarks, and to show the influence that the older 

 mode of investigation still exercises upon the present ; they will also tend to 

 demonstrate how impossible it is to arrive at correct conclusions by starting from 

 indefinite ideas, and how small is the acquisition of scientific knowledge with 

 reference to chemical and physical sciences, even in the most intellectual men. 



INDEFINITE IDEAS OF IRRITABILITY AND IRRITANTS. 



Many external causes, as the atmosphere, heat, electricity, magnetism, chemical 

 agents, mechanical pressure, friction, &c., exercise certain effects upon the whole, 

 or parts of the organism ; in some cases these are similar, in others different. 



These effects are dependent upon a certain number of those active causes, which 

 exert either an external or internal influence upon the organism,* l^he existence 

 of these causes is capable of being defined and measured by the "qualitative and 

 quantitative difference in the effects produced by external causes which indicate 

 a changed condition. The active forces in the organism are, accordingly, appre- 

 ciable by the investigation of those effects which are qualitatively and quantita- 

 tively modified by every external cause. The method pursued by modern 

 pathology is exactly the reverse of the principles advanced, as is proved by a 

 few passages from the celebrated work of Henle, " On Pathological Investiga- 

 tions."* " Irritability is," according to Henle, "every thing which, in acting upon 

 organic matter, alters its form and composition, and consequently its function," 

 p. 223. Far from regarding the separation of causes and their effects as the indis- 

 pensable auxiliaries of knowledge, the author here, as we perceive, includes all 

 imaginable causes of the changes in the form and properties of the organic body, 

 under the term irritability ; and, in the exposition of conditions, this word plays 

 the part of an entity, although this does not comprehend the mode of action of 

 electricity, heat, light, magnetism, or chemical forces, but simply a small part of 

 the action of each of these agents. We need only apply to the following, the 

 definition given above by this author, to perceive how little science gains by such a 

 method. 



" Irritability alters the nervous fibre and its relations to the blood ; but if it do 

 not wholly decompose it, the metamorphosis of matter continues, and is, perhaps, 

 even increased by the irritation, &c." 



FALSE ANALOGIES. 



No one after this will wonder to find, at p. 221 of the same work, an hypo- 

 thesis regarding the mode of action of irritants, although there is not an illusion to 



* Pathologishe Untersuchungen, Berlin,1840. 



