PHYSIOLOGY OF THE INVERTEDRATA. 455 



stability of the organic world ? Nothing would be at one 

 stay. 



" There could be no permanence in anything living. The 

 philosophy of modern biology is that the most complex forms 

 of living creatures have derived their splendid complexity 

 and adaptations from the slow and majestically progressive 

 variation and survival from the simpler and the simplest forms. 

 If, then, the simplest forms of the present and the past were 

 not governed by accurate and unchanging laws of life, how 

 did the rigid certainties that manifestly and admittedly 

 govern the more complex and the most complex come into 

 play ? If our modern philosoishy of biology be, as we know 

 it is, true, then it must be very strong evidence indeed, that 

 would lead us to conclude that the laws seen to be universal 

 break down, and cease accurately to operate, where the 

 objects become microscopic,* and our knowledge of them is 

 by no means full, exhaustive, and clear. Moreover, looked 

 at in the abstract, it is a little difficult to conceive why there 

 should be more uncertainty about the life-processes of a 

 group of lowly living things, than there should be about the 

 behaviour, in reaction, of a given group of molecules. The 

 triumph of modern knowledge is a knowledge — which 

 nothing can shake — that Nature's processes are immutable. 

 The stability of her processes, the precision of her action, and 

 the universality of her laws, are the basis of all science, to 

 which hiology forms no exception. Once establish, by clear 

 and unmistakable demonstration, the life-history of an 

 organism, and truly some change must have come over 

 Nature as a whole, if that life-history be not the same to- 

 morrow as to-day ; and the same to one observer, under the 

 same conditions, as to another. 



" No amount of paradox would induce us to believe that 

 the combining proportions of hydrogen and oxygen had 

 altered in a specified experimenter's hands in synthetically 



* Biichner, Sattler, Grawitz, and others state that certain microbes are 

 capable of being transformed into other microbes. 



