246 Dynamic Theory. 



addition a great number of other forms which, I think, have never been 

 represented. It was quite a new world. " Ehrenberg was convinced that 

 twelve species, described by 0. F. Miiller as belonging to the genus Vor- 

 ticetta, were only different modifications of one and the same species. 

 And yet these twelve forms were so different that "Lamark and Bory de 

 Saint Vincent ranged them under several different genera." 



All these organisms seem to be destitute of any settled scheme of de- 

 velopment. In their modes of reproduction the variations are " almost 

 innumerable," and they have no hereditary bent to dictate any special 

 line of development. There appears to be one impulse behind them all 

 an impulse to grow. But the details of the growth depend exclu- 

 sively on the environment, including the nature of the infusion, tem- 

 perature, &c. Remembering that heredity is the habit of ancestors 

 handed down to their descendants, and that the older it is the more 

 firmly it is fixed ; these loose habits in these little organisms tend to 

 prove a short line of ancestry. It is true that the elementary nature of 

 these organisms makes them indifferent to the source of their food sup- 

 ply, and more susceptible to its reactive influence upon themselves. 



M. Pouchet has adopted an experiment to prove that the ciliated in- 

 fusoria come from the pellicle which forms on top of the infusion. He 

 takes a wide, flat dish, and in its center he places a tall one of small 

 diameter. Into each he puts an equal quantity of filtered organic solu- 

 tion, and covers both under one large glass bell, thus placing both un- 

 der tfre same conditions except as to shape. With a temperature of 68" 

 F. a thick proligerous pellicle is formed in the tall glass and in it plenty 

 of the ciliated infusoria. But when the conditions are reversed, by 

 making the liquid deeper in the shallow vessel than in the tall one, the 

 pellicle becomes thicker and the infusoria abundant in the shallow vessel, 

 while in the tall one the pellicle is thin and the organic product confined 

 to Bacteria. The thickness of the pellicle is necessarily greater over 

 the deeper liquid. 



In solutions containing Bacteria under favorable conditions, according 

 to Bastian, who not only relates his own observations, but cites M. 

 Pineau, M. Pouchet and others in confirmation, processes of a synthetic 

 nature take place by which the Bacteria are consolidated into more com- 

 plex organisms. The scum that forms on the surface of vegetable and 

 other infusions is the seat of these developments. Small tracts of this scum 

 or pellicle become bounded by irregular narrow lines of cleared space, 

 outside of which sometimes there is a border of more densely packed 

 particles which are said to be altered Bacteria. Inside of this bound- 

 ary there occur fewer of the granulations than beyond the border, but in 

 their place a quantity of jelly-like matter makes its appearance. Next, 

 this enclosure becomes marked off by lines crossing in various directions 



