On Muscular Motion and Animal Spirits 271 



mixed abundantly but uniformly with the saline- 

 sulphureous particles of the blood ; so that the spleen 

 really seems to perform these three functions : — 



1. That the nitro-aerial particles which pass in 

 continuous series through the brain, but are not 

 required for natural or animal functions, should be 

 carried into the mass of the blood and properly 

 mixed with it. 



2. That the nitro-aerial particles may be brought 

 in suitable abundance and with a certain control to 

 the viscera devoted to the digestion of food. For 

 as these viscera are filled with food or empty, so they 

 have need of a greater or of a less afflux of fermentative 

 particles. 



3. That the nitro-aerial particles in a condition of 

 motion and vigour should, when most intimately 

 mixed in the substance of the spleen with the saline- 

 sulphureous particles of the blood, excite in the mass 

 of the blood such an effervescence as is fitted to 

 bring its saline-sulphureous particles to a proper 

 volatility. 



As to the former uses here assigned to the spleen, 

 the plexus and various communications among the 

 splenetic nerves and among those distributed to the 

 other viscera seem to confirm them. For by the 

 communications it is brought about that the nitro- 

 aerial particles are brought to the viscera serving 

 for the digestion of food, and for other natural 

 functions now in greater and now in less abundance 

 as there is need, and what of the nitro-aerial particles 

 is over is turned aside into the spleen. 



And in this we may seek the reason why, when 

 the spleen is affected by scirrhus, or obstructed in 

 any other way, the patient suffers from eructation 

 and hypochondriac flatus : for inasmuch as the nitro- 



