THE SKIN AND COMMON SENSATION. 969 



pain. " Painful " is the affective colour of many psychical states 

 both more complex and less complex. 



There are intellectual processes with negative affective tone, and 

 simple sensations with negative affective tone. Of the latter, those 

 belonging to the projicient senses are less strongly coloured than 

 those of the non-projicient. It is the " sense pains " of the non- 

 projicient senses that constitute bodily or " physical " pain. Physical 

 pain is so eminently obtainable from the skin, that about the question 

 of cutaneous pain discussion as to existence of a specific sense of 

 pain is chiefly turning. 



Admitted that the disagreeableness of an intense light or of a discord 

 is not fully comparable with the " pain " of scalded skin, that admission 

 is not tantamount to allowing that cutaneous pain is the product of a 

 specific " pain sense." It can be said that all parts of the body that can 

 produce pain are endowed with nerve fibres normally ministering to a 

 group of senses that can be classed together as yielding common 

 sensation, and that these nerve fibres only under stimulation excessive 

 either in intensity or duration or spatial extent, produce pain. By 

 common sensation is understood that sum of sensations referred, not to 

 external agents but to the processes of the animal body. Its " object " 

 is the body itself — the material "me." Sensations derived from the 

 bodily tissues and organs possess strong affective tone ; while the sensa- 

 tions of special sense are relatively free from affective tone. 



The scope of the term " common sensation " no doubt has varied somewhat 

 with different authorities. 1 Adopted in contradistinction to "special sensa- 

 tion," the ordinary meaning of the word does not immediately explain its 

 technical use. All afferent nerve fibres were considered to supply impressions 

 to the common sensation of consciousness ; the nerves of the special 

 senses were considered to supply, over and above the common sensation 

 which they each supplied in common, impressions of special sensation, each 

 peculiarly its own, optic nerve, visual, etc. Magendie's experiments (1825) of 

 scratching the retina with a needle, exciting the eighth cranial nerve, etc., did 

 something toward removing from the special sense nerves the ascription of 

 functions of common sensation. Johann Midler, 2 no doubt under the influence 

 of Kant's philosophy, brought forward the law of the specific energies of sense. 

 Earlier writings by Purkinje, Elliot, Charles Bell, and Autenrieth had paved 

 the way to this ; and the limit of the law has been affected since by the 

 Darwinian principles of evolution and adaptation. J. Midler went so far as not 

 to concede the existence of common sensation (Gemeingefiihl) as distinct from 

 touch. He reckoned to the category of tactual the sense impressions derived 



1 For instance, compare E. H. Weber, Wagner's "Handworterbuch," Bd. iii. S. 2, with 

 J. Henle, "Allg. Anat.," Leipzig, 1841, S. 728. By some (e.g. K. Vierordt, "Grnndriss," 

 Tubingen, 1877, S. 488), the term is made to include all those sense impressions in which 

 we can discover or observe alteration of our own state of impressibility. By this definition 

 are included in common sensation the so-called " subjective " sensations, originated in the 

 special (so-called " objective") senses by internal stimulation, i.e. by conditions arising in 

 the body itself. In this connection it may be remembered that the excitation of a skin 

 nerve in its course (e.g. faradisation of ulnar trunk at elbow), it was at one time taught 

 evoked pain only, not sensations of touch. To refute the teaching, the experiment has only 

 to be repeated. The sensation obtained is usually not painful, although always "strange." 

 Its strangeness is no doubt explicable by the combination in simultaneous excitement of 

 nerve fibres in groupings never previously experienced, dependent on tlieir mere position in 

 the nerve trunk. Some are included and some left out in unwonted fashion. Hence the 

 punctiform character of the reference. The above wider scope of the term common sensa- 

 tion (Gemeingefiihl in weiterem Sinn) seems inconvenient and is not adopted here. 



2 "Zur vergleichenden Physiologie des Gesichtsinnes," 1826; " Ueber die phantasti- 

 schen Gesichterscheinungen " ; and " Handbuch der Physiol.," 1832 to 1840. 



