45 



The theory of Lucretius was, that the animus or mens, the intel- 

 lectual pait of our nature, was distinct from the anima or vita 

 portion, and this has been generally accepted since his day. The 

 belief that life constitutes a '* materia vita diffusa" was adopted by 

 the celebrated anatomist and physiologist, John Hunter, and has 

 been reproduced in the works of Leuenhoek, Penault, and others. 

 Leibnitz, Haller, Spallanzani, and Priestly, with other moderns, 

 have adopted, in its essence, the idea of Lucretius, as regards the 

 semina rerum, and express their general belief in the existence of 

 various species of organised atoms. The dogma, however, of the 

 " pre-existence of germs " has been annihilated by the still more 

 recent arguments and experiments of the French physicist, M. 

 Flourens. 



The lecturer proceeded to remark that all merely imaginary 

 theories had given place to the solid basis of truth, established by 

 the progress of true inductive philosophy, and almost in our own 

 day by the application of the science of histology. These had re- 

 duced all theories respecting Life into what may be noticed with 

 sufficient distinctness as the physical and the vital theory. 



The process by which the physical theory of Life has been arrived 

 at may be thus concisely stated, and in the statement we shall best 

 attain a distinct view of the theory itself. 



While the manifest distinction of substances cognizable to our 

 senses into inorganic and organic remains, a process has been at- 

 tempted of tracing a continuous line of connexion between inani- 

 mate insensate matter, and sentient organized structures ; and such 

 attempts, we must acknowledge, have not been made without a 

 measure of at least apparent success. 



Thus, the semblance of living and voluntary motion may be 

 noticed in the particles of such minerals as are subjected to the 

 process of crystalization. Chemical and electrical action on many 

 inorganic substances will readily supply to those who are familiar 

 with these departments of physical science, other instances of 

 simulated vital action. When, however, we come to the border 

 region, so to speak, of the mineral and vegetable kingdoms, the chain 

 of connection sought becomes more apparently real. Carbonic 



