MODES OF ORIGIN COMPARED 47 



if the combinations constituting 'living matter' are very much more 

 complicated and unstable than those of the crystals to which we 

 have just been referring, then the forms assumed by such sensitive 

 matter, under different conditions, ought to be excessively variable 

 and capable of undergoing remarkable transformations. 



Let us turn now to the question of the mode of origin of crystals, 

 and the possible mode of origin of lowest organisms, so far as this 

 is open to mere observation. 



The question in each case is, whether by mere concurrence of 

 certain physical conditions, aiding and abetting the inherent 

 properties of the respective different material combinations, some 

 kinds of matter can fall into modes of combination called 

 ' crystalline,' whilst other kinds are capable of falling into modes 

 of combination called ' living ' ; or whether, in each case, a pre- 

 existing ' germ ' of the particular kind of matter is necessary, in 

 order to determine, in suitable media, either of these modes of 

 combination. Are we to believe that crystals can appear in no 

 solution whatsoever without the pre-existence in that solution of 

 certain crystalline germs ; and similarly that living things can arise 

 in no solution whatsoever without the pre-existence in such 

 solution of living germs ? 



The very mention of this question in connection with the origin 

 of crystals may seem to some people to be quite absurd, because 

 they may have been in the habit of believing that crystals could, 

 and do, habitually come into being de novo, without the agency 

 of pre-existing crystals. But in spite of the fact, that the majority 

 of people are quite content to believe that crystals originate in 

 obedience to purely physical conditions, and independently of 

 pre-existing ' crystalline force ' ; still, facts somewhat similar to 

 those which are to be met with in connection with the sister 

 problem, long induced many chemists seriously to question the 

 possibility of the de novo origination of crystals. 



The way in which this problem was at last solved has been ably 

 brought out by Prof. Leo Errera in an essay entitled " A propos 

 de generation spontanee," ' an abstract of a portion of which I 

 subjoin. 



He points out that in 1865 Violette and Gernez demonstrated, 

 independently, that crystallisation was brought about at ordinary 



« " Revue de I'Universite de Bruxelles," t. v., 1899-1900, Mai. 



