167 



muscular fibres: this is unequivocal in regard to the organic life, 

 which we are now considering, and is borne out by a similar testi- 

 mony in the animal department Which we shall presently mention. 

 22. But some injuries of connected parts, where there is no 

 dependence, as on properties received, may destroy the health, or 

 render extinct the living properties of a secondary seat. As an 

 example of this law, a ligature on one or more of the brachial 

 nerves may in a rabbit destroy the vitality of the foot, occasion- 

 ing the sloughing of the skin, muscles, &c. below the place of 

 injury; but the same nerves may be divided at the place where 

 the ligature might have been applied, and the vitality of the skin, 

 muscles, c. of the foot and leg will continue. The former is a 

 clear case of influence by communication, assumed in consequence 

 of the injury; and not of influence by privation, because the 

 division of the nerves, with the preservation of vitality in the in- 

 ferior seats, proved that the vitality in these seats was independent 

 of that superior seat, by a preternatural condition, of which the 

 vitality of the former may be modified or destroyed. 



23. There appear to be cases in which parts may be naturally 

 dependent by communication, and yet preserve an unimpaired 

 condition under a separation; but these cases are equivocal, by 

 reason that the continuity of vessels may perform the relative 

 ottice otherwise imputed to spiritual continuity. Thus, to exem- 

 plify such a case, suppose such a defined spot 

 of a nerve in an extremity as 7 communicating 675 

 with 6 and 5. If the communication with 6 I " I ' : 



be cut off at the line 8, then the properties 

 will be maintained at 7 by communicating 8 9 



with 5. If cut oflfby the line 9, the properties 

 at 7 will be maintained by communicating with 6; and that the 

 dependence of the properties at 7 is by communicating either with 

 5 or 6, or with both, is proved by the fact that if the two sections 

 8 and 9 are made at the same time, and the portion of nerve 7 

 thus separated totally from its connections, it will die and its struc- 

 ture fall to decay. 



24. These laws apply to, and are deduced in conformity with 

 the modes of change in general instances. They are also by their 

 illustration shewn to belong to animal bodies. It remains to in- 

 vestigate the agents concerned in the dependence spoken of; and 

 this must be done by a retrospect of some former doctrines, con- 

 necting them closely with the business of this section. 



25. It cannot be proved that the life or the organic spirit of 

 any seat is essentially dependent upon that formed or existing 

 elsewhere: for though it is admitted that a portion of a structure 

 when separated from the rest cannot live, yet there is in such por- 

 tion not only a separation from a contiguous living principle, but 

 its sources of blood are also cut off. It is shewn in a former article 

 that the terms of the maintenance of life are comprised in the 

 existence of an organic spirit properly identified, and in the sub- 



