179 



furnish a few hints upon the objects of the investigation, or to ex- 

 hibit another example of the general conformity and subordination 

 which we have hitherto traced. 



7. If food is put into the stomach of an animal some hours 

 after death it will not be reduced to chyme. The stomach may 

 contain those secretions which are formed preparatory to a meal, and 

 which furuish the chymicals produced by the stomach: our regard 

 also may be had to temperature ; yet this food will not be digested 

 as in the living stomach, but, if of the animal kind, will follow the 

 fate of the animal structures, it will be decomposed by putrefaction. 



8. As food will not be digested unless life is present, it i 

 necessary to infer that life is essential to digestion. 



9. But it is not a mere principle of life of any sort that will 

 accomplish this end. How, it will be asked, is this ascertained! 

 A digestible substance may be well impregnated with gastric secre- 

 tion, and in this state sewed under the skin of an animal, by which 

 it will be as effectually surrounded by a principle of life as in the 

 stomach; yet, without making the experiment, it may be almost 

 affirmed that this substance will not be reduced to chyme. That it 

 should is contrary to analogy; for, in the experiments and operations 

 of grafting animal substances, we find that the foreign ones are 

 never made chyme, but that they are dissolved by putrefaction, 

 except in cases where an union takes place between them. 



10. The organic spirit of the stomach, then, is one which has 

 peculiar properties, in addition to those (many times specified) which 

 are sufficient to characterize a vital principle. The relation, or 9 

 relation, of these properties with food is to assist in its digestion. 



11. The secretions of the stomach furnishing on the part of 

 the animal, as has been said, the chymicals which are related with 

 food, it is supposed, contribute towards digestion; but their share 

 in this process is not ascertained, although experiments have been 

 instituted with something like this view. 



12. The general history of these secretions, made up of consti- 

 tuents, which chymistry to a certain extent can analyze, is this: 

 Tubes, variously connected, continuous with the blood-vessels, 

 called their secerning extremities, open into the stomach. These 

 tubes separate, and then excrete into the stomach peculiar fluids. 

 The fluids which it is their function to form, cannot be produced by 

 any known hydraulic imitation; they are never known to be pro- 

 duced but whilst life is present. It is hence to be inferred, that 

 blood supplies a material, certain parts of which are so related 

 with the vital properties, inhering with a certain order of vessels, 

 that the end of their relaiion is to produce the secretions in question. 



13. Thus the participation of chymical agents in the process 

 of digestion may be said to be the effect of a previous operation of 

 certain properties of life. The history of this life is to be a little 

 further traced. 



14. It has been before said thai our means of analysis are too 

 imperfect to admit a specification of the share which the agent* 



