87 



7. For many tissues which produce these phenomena a com- 

 plete rest is scarcely possible. The phenomena take place, in 

 appearance, spontaneously, and with as much energy as the 

 temperature is higher. 



8. The faculty of producing these phenomena decreases at the 

 time they are going on, in proportion to their intensity and 

 duration, and in inverse ratio to the nutritive reparation which 

 simultaneously takes place. 



9. Reparation thus incessantly supplying for expenditure, it 

 is not possible, with regard to most of these phenomena, and as 

 long as circulation goes on, to destroy entirely the faculty of 

 originating them ; or rather, as soon as we have succeeded in 

 destroying that faculty, it is reproduced by nutrition. 



10. Expenditure dependent upon action, being followed by a 

 great activity in the nutrition, it happens that, if the action be 

 frequently renewed, there is an excess of nutrition and a consi- 

 derable increase of the faculty of acting. 



11. When the faculty of acting has been increased in virtue 

 of the preceding reasons, within a certain limit, an equilibrium 

 exists between the expenditure and the reparation, and the in- 

 crease no longer takes place. 



12. As it is possible for nutrition to take place in the tissues, 

 although the nutritive fluid is not actually circulating in them, 

 and provided that a certain amount of it exists in them, the 

 faculty of acting may be increased in parts where circulation is 

 stopped. 



13. Although circulation and consequently reparation, are 

 more active in summer than in winter time, at least in cold- 

 blooded animals, the faculty of acting becomes more consider- 

 able in winter than in summer time, because the spontaneous 

 expenditures abovementioned, and those due to external stimuli, 

 or dependent upon the will, are by far less considerable. 



All the preceding laws may be summed up in the following : 

 The intensity of the faculty which animal tissues possess, of 

 producing the vital phenomena, seems to be in a direct ratio to 

 the intensity and duration of the nutritive reparation, and in an 

 inverse ratio to the intensity and duration of the existence of 

 these phenomena. 



