TO PHYSICS AND PATHOLOGY. 37 



ERRONEOUS CONCLUSIONS DRAWN FROM BRINGING ONE CAUSE 

 TOO PROMINENTLY FORWARD. 



Erroneous combinations of conclusions of another kind are formed, when in the 

 explanation of a natural phenomenon we only keep in view one of the many 

 causes on which it is dependent, ascribing to it an active importance which it does 

 not possess in and for itself, but merely receives from the presence of other causes. 

 Thus, for instance, Schleiden bases his theory partly upon an untenable atomism, 

 partly upon false mechanical principles, when he says, in his " Elements of 

 Scientific Botany,"* "that fermentation and putrefaction are the effects of the 

 communication of a motion, and that the amount of the motion will be measured 

 by the product of the mass into the velocity. One part of diastase is said to 

 extend its decomposing power over 1000 parts of starch (but this is. an error, 

 since, according to Guerrin Varry, one portion of diastase acting upon 60 of starch, 

 gives only 10.3 of sugar. The relation of 16 of starch to 1 of diastase, gives 

 only 14 of sugar.) We must, therefore, assume in an atom of diastase a velocity 

 1000 times greater than would be necessary for the decomposition of an equal 

 weight of starch. Here we see that a gigantic edifice of crowded hypotheses has 

 been erected upon the most untenable basis, in order to support a false opinion. 

 On the other hand, the objection started as to the impossibility of one body at rest 

 setting another in motion, borrowed from the atomic method of explanation, is 

 likewise physically false ; since gravitation, magnetism, and electrical attraction 

 are nothing but mere examples of motion being imparted by one body at rest to 

 another." 



CORRECTION OF SCHLEIDEN'S VIEW. 



As to what regards diastase, and its action upon starch, Schleiden has forgotten 

 to take into consideration the time which is necessary to effect the conversion into 

 sugar. The view which he contests, does not presuppose that the molecules of 

 the diastase possess a greater velocity, but that the surrounding deposition of the 

 molecule of starch had gone on while the motion in the diastase molecule still 

 continued, and, consequently, before a state of equilibrium had been established in 

 the latter. Nothing is to be understood by a communication of motion, but that 

 the molecules of starch are kept in contact with the molecules of the diastase, as 

 if they were parts or constituents of it. The action of the diastase in a limited 

 time depends, therefore, upon the number of the molecules of starch that can come 

 in contact with the molecules of the diastase in the same period of time. The 

 number of the molecules of diastase affect the time and the process of its conver- 

 sion into sugar ; the action disappears with the presence of diastase, and by a 

 double or triple quantity of diastase the time of the conversion is shortened, or a 

 larger quantity of starch is converted in sugar. 



THE MEANS BY WHICH MOTION OCCURS. 



As to the view advanced regarding gravitation and electricity, as instances of the 

 motion of one body through another at rest, we must take into consideration 

 that a body at rest may pass into a condition of motion in two essentially different 

 modes. 



FIRST : BY THE COMMUNICATION OF A MOVING MASS. 



1. By the communication of the moving mass of a body already in motion, as 

 by means of a blow for instance, the action of the hammer on the nail, of water 

 on the mill wheel, or wind upon the sail. 



* Grundzuge der Wissenschaftlichen Botanik, 1845, p. 282. 



