1893.] 



Pathology among Biological Studies. 



121 



This dispute about the irritability of muscles has continued far 

 into the present century ; its long duration becomes intelligible only 

 when we bear in mind that, without the most exact knowledge of its 

 historical development, even the very statement of the question is 

 liable to be misunderstood. 



As a matter of fact, so far as we know, the nerves are not contrac- 

 tile, like the muscles ; on the other hand, the muscles are not only 

 contractile, but are also irritable. Irritability and contractility are 

 not identical, even when they occur in the same part. The nerve 

 current, on the other hand, cannot be compared with the blood stream ; 

 it does not consist in the movement of a fluid, but is of electrical 

 nature, and hence there is no need for its production of a contraction 

 of the nerve-tubes. 



It was also an erroneous conclusion that every irritated part con- 

 tracted. Instead of contraction, secretion, or, under certain circum- 

 stances, a more vigorous nutrition, may occur as the final result of 

 irritation. Hence we use a more comprehensive term in order to 

 express this final result, and call all forms of it "actions." While 

 Glisson defined all " actio propria sic dicta " as " motus activus," we 

 distinguish different kinds according to the nature of the effects, or, 

 otherwise expressed, according to the direction of the activity (nutri- 

 tion, formation, and function) ; but we agree with the above thinker 

 in the opinion that no vital energy is ever set free without stimulus : 

 and that, consequently, every action is of an irritative nature. In this 

 irritation, according to my idea, consists the " principium dividendi, " 

 according to which we must distinguish between active and passive 

 processes of life, and in this way we gain also a basis for the funda- 

 mental division of pathological elementary processes. How much 

 work has been necessary in order to render this conception possible ! 

 And how great, even now, is the number of our colleagues who 

 have not fully accepted it ! The reason for this difficulty is two- 

 fold. 



Most of the vital actions of life, whenever they manifest themselves 

 by visible events, are of a compound nature. As a rule, parts very 

 various, at times wholly unlike, each with its specific energy, combine 

 to produce them. Not unfrequently it thereby happens that in the 

 visible sum of final effects one part behaves in an active, the other in 

 a passive, manner. It is only the most minute analysis of the pheno- 

 menon, tracing it right back to the elementary parts, which allows 

 the total result to be resolved into its components ; such an ana- 

 lysis cannot, as a rule, be expressed in current language, except 

 at great length. JSTo language in the world is rich enough to possess 

 special expressions for each such combination. Only too often we 

 help ourselves out of the difficulty by regarding the compound 

 phenomenon as a simple one, and by expressing its character accord- 



