7 20 THE POPULAR SCIENCE MONTHLY. 



oxygen and of silver begin to aggregate independently into crystals of 

 oxide of silver ; in a second increment of time the operation of the 

 same causes produces similar results, only now part ol the new crys- 

 talline matter forms in connection with the preexisting germs of crys- 

 tals, though part of it may still aggregate independently. During a 

 third, a fourth, and in all succeeding increments of time, in which the 

 same causes operate amid similar conditions, similar results must en- 

 sue. But, taking the process of origination which occurs in the first 

 increment of time, would Prof. Tyndall have us believe that it is in 

 any way different from that of growth which takes place in a second, 

 third, or fourth increment of time ? Does not the very fact that origi- 

 nation and growth so often occur simultaneously in the case of crys- 

 talline matter, and under the influence of the same causes, show us 

 that the two processes are intrinsically similar, and that conditions 

 favorable for growth are also likely to be favorable for origination ? 

 And if this be true for crystalline matter, may we not infer that it 

 would also be true for living matter? These are questions neither 

 asked nor answered in any definite manner by those whose opinions I 

 have already cited. They are, however, questions by no means un- 

 worthy of an attentive consideration. 



Although, as a general rule, conditions favorable for the growth of 

 any particular kind of crystalline matter are likely to be favorable for 

 its origination, still it must be acknowledged that the presence of a 

 crystal will occasionally lead to its growth in a medium in which simi- 

 lar crystalline matter had previously shown no tendency to form inde- 

 pendently — even in cases where the introduction of a non-crystalline 

 nucleus would not be able to determine a similar formation of crys- 

 talline matter. In spite of the general law, therefore, that conditions 

 favorable for the growth are also favorable for the origination of crys- 

 talline matter, we are compelled to admit that growth may be deter- 

 mined under certain conditions where origination does not occur, and 

 that the presence of preexisting crystalline matter favors the process. 

 Now, a distinction of the same kind undoubtedly obtains in the case 

 of living matter. We know, quite positively, that, although Bacteria 

 will not originate in a previously-boiled ammonic tartrate solution, or 

 " Pasteur's solution," the addition of a few of these organisms (all 

 other conditions remaining the same) will soon occasion a very con- 

 siderable growth of the living matter of which they are composed. 1 

 We are thus reduced to ask whether the influence of the preexisting 

 nucleus is relatively more potent in the case of living matter than it is 

 in the case of crystalline matter ? This is a question which unfortu- 

 nately we are unable definitely to answer. But, so long as we have no 

 positive knowledge on this subject, we surely have little right to infer 

 that processes both of origination and of growth continue in the case 

 of crystalline matter, while the process of growth alone survives in the 



1 " The Beginnings of Life," vol. i., p. 325. 



