l66 LIFE AND DEATH. 



and that it is in its protoplasm that the chemists 

 should be able to find the compounds, the special 

 albuminoids, which, par excellence, form living matter. 



§ 3. The Physical Constitution of Living 

 Matter. The Micellar Theory. 



Physical Constitution of Living Matter. — Micro- 

 scopic examination does not take us much farther. 

 The microscope, with the strongest magnification 

 of which it is capable at present, shows us nothing 

 beyond these links of aligned microsomes forming 

 the species of protoplasmic thread or mitome, whose 

 cellular body is a confused tangle or a very tangled 

 ball. It is not probable that direct sight can pene- 

 trate much farther than this. No doubt the micro- 

 scojae, which has been so vastly improved, is capable 

 of still further improvement. But these improve- 

 ments are not indefinite. We have already reached 

 a linear magnification of 2000, and theory tells us 

 that a magnification of 4000 is the limit which cannot 

 be passed. The penetrating power of the instrument 

 is therefore near its culminating point. It has already 

 given almost all that we have a right to expect 

 from it. 



We must, however, penetrate beyond this micro- 

 scopic structure at which the sense of sight has been 

 arrested. How is this to be done? When observa- 

 tion is arrested, hypothesis takes its place. Here 

 there are two kinds of hypotheses, the one purely 

 anatomical, the other physical. Anatomically, beyond 

 the visible microsomes there have been imagined 

 invisible hyper-microscopic corpuscles, the plastidules 



