APPENDIX B. xxvu 



and develop, there also they may be quite capable of origi- 

 nating. 



{h). The matter of the crystals of ammonic tartrate is, 

 by a re-arrangement of its atoms, quite capable of giving 

 origin to organizable compounds, and seems, moreover, to 

 lapse into these new modes of combination, with especial 

 facility — a facility far superior to that which is displayed by 

 many other ammoniacal salts\ If a small quantity of tartrate 

 of ammonia is dissolved in a watch-glass with distilled water, 

 and is protected as much as possible from dust and evapora- 

 tion by being covered with two or three inverted glasses, it 

 will be found, during warm weather, that in the course of two 

 or three days the bottom of the watch-glass is covered by a 

 number of minute microscopic crystals, interspersed amongst 

 a mixed layer composed of plastide particles, Bacteria, and 

 minute Torula cells ^. These organisms form, in fact, almost 

 as freely (though not so quickly) in this ammoniacal solution, 

 as they do in an ordinary infusion containing organic matter. 

 There can be little doubt that the amount of ammonia and 

 of tartaric acid actually diminishes, and that the elements of 

 these enter more or less directly into the new combinations 

 of which living matter is composed ^. 



{c). It may be said that such changes do not take place by 

 the mere action of physical forces upon the organic fragments 

 and the molecules of the dissolved tartrate of ammonia, and 

 that the presence of pre-existing living matter is necessary 

 for the initiation of such molecular re-arrangements. In 



^ See Appendix C. pp. xlvi-1. 



"^ In saline ■ solutions I have generally seen "the organisms first, and 

 have found them accumulate principally at the bottom of the watch- 

 glass or other vessel in which the solution may have been contained, 



3 Saline solutions in which spores of fungi were placed, having been 

 analysed previously by M. Pasteur, were again analysed by him after the 

 plants had grown for a time. The proportion of ammonia and of other 

 ingredients was found to have undergone a diminution correlative with 

 the growth of the plants. 



