824 OF THE STRUCTURE AND FUNCTIONS OF MUSCULAR TISSUE. 



the latter, occasions the immediate cessation of the heart's action, though 

 they may be gradually removed without any considerable effect upon it. 

 Severe concussion has the same effect ; hence the syncope which immediately 

 displays itself. It is sometimes an important question in forensic medicine, 

 whether an individual who has died from the effects of a blow upon the 

 head, could have moved from the place where the blow was inflicted. If 

 there be found, as is frequently the case, no sensible disorganization of the 

 brain, the death must be attributed to the concussion, and must have been 

 in that case immediate. If, on the other hand, effusion of blood has taken 

 place within the cranium to any considerable extent, it is probable that the 

 first effects of the blow were in some degree recovered from, and that the 

 circulation was re-established. It is not essential, however, that the impres- 

 sion should be primarily made upon the Cerebro-spinal system. The well- 

 known fact of sudden death not unfrequently resulting from a blow on the 

 stomach, especially after a full meal, without any perceptible lesion of the 

 viscera, clearly indicates that an impression upon the widely-spread coeliac 

 plexus of Sympathetic nerves (which will be much more extensively com- 

 municated to them when the stomach is full than when it is empty) may 

 cause the immediate cessation of the heart's action, in the same manner as 

 a violent injury of the brain or spinal cord. 1 In all these cases the whole 

 vitality of the system appears to be destroyed at once ; for the processes 

 which would otherwise succeed to the injury, and which after other kinds 

 of death less sudden in their character, produce evident changes in the part 

 of the surface that has immediately received it, are here entirely prevented. 

 An instance is on record in which a criminal under sentence of death deter- 

 mined to anticipate the law by self-destruction. Having no other means of 

 accomplishing his purpose, he stooped his head and ran violently against 

 the wall of his cell ; he immediately fell dead, and no mark of contusion 

 showed itself on his forehead. The same absence of the usual results is to 

 be noticed in the case of blows on the stomach. The influence of severe 

 impressions on the nervous system in diminishing, when it does not alto- 

 gether destroy, muscular irritability, is well seen in the operation of severe 

 injuries affecting vital organs, or extending over a large part of the surface, 

 in depressing the heart's action ; to which attention has already been di- 

 rected ( 241). 



674. From a general consideration of the phenomena of Irritability, we 

 can scarcely do otherwise than acquiesce fully in the doctrine of Haller, 

 which involves no hypothesis, and which is perfectly conformable to the 

 analogy of other departments of Physiology. He regarded every part of 

 the body which is endowed with irritability as possessing that property in 

 and by itself; but considered that the property is subjected to excitement 

 and control from the nervous system, the agency of which is one of the 

 stimuli that can call it into operation. It may be desirable briefly to sum 

 up the facts by which this doctrine is supported. 1. The existence in vege- 

 tables of irritable tissues, which are excited to contraction by stimuli di- 

 rectly applied to themselves, and which can be in no way dependent upon 

 or influenced by a nervous system. 2. The existence in animals of a form 

 of muscular tissue which is especially connected with the maintenance of 

 the organic functions, and which is much more readily excited to action by 

 direct stimulation than it is by nervous agency. 3. The fact that by the 

 agency of these the organic functions may go on (so long as their requisite 

 conditions are supplied) after the removal of the nervous centres (of the 

 Cerebro-spinal system at least), and when these were never present; rendering 



1 For examples of this see Lancet, 1870, vol. i, p. 276. 



