On Muscular Motion and Animal Spirits 281 



cause ; for these symptoms seem in the said diseases 

 to come not so much from a deficiency of animal 

 spirits as from a disorder of the blood and of the 

 muscular flesh. 



We may note by the way, that the slighter 

 convulsions, like those tvvitchings of the tendons 

 which trouble many in continued fevers, may to some 

 extent arise from a diseased condition of the muscular 

 flesh, in so far as not only the saline-sulphureous 

 but also the nitro-aerial particles passing through the 

 now nearly wasted away parenchyma of the flesh, 

 are transmitted into the motor parts, and by their 

 mutual effervescence the often slight contractions of 

 the fibrils are, as is likely, produced. 



From what has been said, the reason can be given 

 why bodily exercises are so useful in the icteric 

 disease and scorbutus, and also for warding off the 

 paroxyms of intermittent fevers. For in exercise the 

 nitro-aerial particles are sent in greater abundance 

 into the mass of the blood by the more intense 

 respiration, and the motion of the blood is much 

 promoted by the contraction of the muscles ; whence 

 it comes about that the fermentation of the blood 

 is increased and it is comminuted and worked up. 

 Further, the saline-sulphureous particles brought to 

 vigour are secreted from the blood and used up in 

 muscular contraction, and it is by their excess in the 

 mass of the blood that febrile heat is excited, as has 

 been elsewhere said. 



