278 M. Pasteur on Aspartic and Malic Adds. 



actions. The first class of phsenomena would depend solely upon 

 the particular nature and the total mass of the different ingredients 

 contained in the corpuscles of each svibstance, as also upon the 

 special properties which might naturally appertain to each of 

 these taken as a whole. The latter class of pha^nomcna would 

 depend, fui'ther, upon the position which each ingredient might 

 occupy in the corpuscle, upon their relative arrangement, and 

 upon the coufigm-ation of the entire corpuscle. 



These two orders of effects of attractive forces are realized with 

 the greatest strictness in the motions of the planetary bodies 

 which compose our planetary system; and they can be easily 

 observed there. The general motions of revolution which the 

 planets execute in their orbits, and the occasional derangements 

 which they undergo, take place without any appreciable differ- 

 ence, as if their masses wei-e individually concentrated into a 

 mathematical point coinciding with their centre of gravitation. 

 This, then, is the first order of pheenomena. But the relative 

 situations of the elements of mass which compose the bulk of 

 each planet have a sensible and determinate iufiuence upon the 

 oscillations of the fluids which cover them, and upon the various 

 motions which each executes round its centre of gravity, inde- 

 pendently of its constant rotation on its axis. This represents 

 the second order of phsenomena. In a mathematical point of 

 view, the one and the other ought to take place with analogous 

 characters in all the systems of free bodies possessing reciprocal 

 actions which are exercised at a distance. But the effects which 

 belong to them may have relations entirely different from those 

 which we observe in our planetary system. Their phases of 

 simultaneous accomplishment may become so sudden and so in- 

 terwoven together, that observation, although knowing the fact 

 of their existence, is unable to detect them. 



This is exactly what happens in chemical reactions ; and it may 

 readily be conceived why this should be the case, when the me- 

 chanical conditions of the two classes of phsenomena are com- 

 pared. The permanent bodies of our planetary system have all 

 a nearly spherical form. The intei-vals by which they are sepa- 

 rated always remain very great in comparison to their actual 

 dimensions. At those distances, the attraction proportional to 

 the masses and recipi'ocal to the square of the distances is the 

 sole force which has any appreciable influence upon their motions. 

 They move in a space virtually destitute of resistance ; and their 

 masses remain constant, or at least, during the ages that they 

 have been observed, no alteration has taken place which could 

 be detected. Finally, their number is small ; and their masses too 

 are all very small compared with that of the principal body round 

 which they revolve. This concurrence of circumstances gives to 



