RELATIONS OF THE ORGANS TO ONE ANOTHER. 617 



the normal composition of the cell-protoplasm. We mention these ideas 

 merely to show that we are able to get along perfectly well without the 

 conception of exhaustion. On the other hand, we must remember that 

 the various nerve-cells are not necessarily all of uniform nature. It is 

 perfectly possible that the different groups of nerve-cells, which serve for 

 the exercise of definite functions, are differently constituted chemically 

 and possess a perfectly distinct metabolism, and that the key to the 

 cause of the different diseases of the system is to be sought in this fact. 

 The familiar diseases of the nervous system which are always, within quite 

 narrow limits, localized along definite paths are of quite particular interest 

 in many directions. Here the close connection between nervous and 

 muscular tissue becomes very evident. 1 



We have repeatedly spoken of the direct and indirect influence of the 

 nervous system upon all the organs of the body. It is quite impossible to 

 define this more closely, i.e., we cannot in any way explain the nature 

 of the conveyance of sensation. We merely know that the nerve-fibers 

 are merely outgrowths of the nerve-cells with which they form a unit. 

 The former are in contact with the organs usually by means of a character- 

 istic end-apparatus. It does not seem at all impossible that physiological 

 chemistry, together with physical chemistry, will eventually throw light 

 upon this process. It can hardly be doubted that definite changes, 

 whether in the end-apparatus or in the nerve-cells, give rise to definite 

 functional expressions of the nervous tissue. 



Before we take up the relations of the musculature to the other organs, 

 we will consider briefly a reaction which is common to both muscle and 

 nervous tissue, namely the so-called heat-rigor. 2 If a muscle is gradually 

 heated, it loses at a definite temperature its power of being stimulated, 

 and contracts. The cause of this heat-rigor is the coagulation of the 

 albumin, and it may be shown that this does not take place all at once, but 

 in stages. Different albumins present in the muscle coagulate at different 

 temperatures. The nerves behave in exactly the same way. They also 

 show a heat-rigor. The lowest temperature at which one of the albumins 

 coagulates, corresponds to the time that the nerve ceases to be capable 

 of response to stimulation. Here, as in the case of muscles, there is a 

 contraction. 



As is well known, the albumins in muscles coagulate after death. Rigor 

 mortis results, and this does not attack all the different muscles at one 

 time. Its appearance after death also occurs at different intervals of 

 time. The cause of death-rigor has been much studied. It is certain 



1 Cf. Robert Bing: Deut. Arch. klin. Med. 86, 199 (1905); and Deut. Z. Nervenheilk. 

 26, 163 (1904); and Ueber angeborene Muskeldefekte. Inaug. -Dissert. Basel (1902). 



2 Brodie and Richardson: Philos. Trans. London, Series B, 191, 127 (1899). Vernon: 

 J. Physiol. 24, 239 (1899). O. von Fiirth: Z. physiol. Chem. 31, 338 (1900). 



