THE MECHANISM OF LIFE 



541 



flat flame, however, the molecules of illuminating gas are in such 

 a numerical relation to those of the oxygen of the air that active 

 combustion takes place. The change of the substance of the 

 flame through the incoming gas and the surrounding air is, how- 

 ever, so regulated, that at the same place the same kinds of 

 molecules constantly come together in the same number. As a 

 result, the same form of flame with its differentiations is main- 

 tained continually. But if the stream of matter be altered by 

 letting less gas pass out, the form of the flame also changes, 

 because now the mutual position of the molecules of illuminating 



FIG 264 Stentor Rceselii. A, Cut across at*. B and C, The two pieces have become regenerated 

 into complete Stentors. The clear extended mass in the interior is the nucleus. 



gas and of oxygen is changed. It is thus seen that such a flame, 

 even in its details, presents exactly the same conditions that we 

 have found to be important in the construction of the cell-form. 



Another interesting group of phenomena of form-construction 

 is at once clear from this point of view, namely, the phenomena 

 of regeneration. If a cell best an infusorian cell that is provided 

 with very characteristic differentiations of its surface, such as the 

 delicate Stentor Rceselii be cut into two pieces, so that each con- 

 tains a part of the nucleus and hence possesses the value of a 

 cell, in a short time, as has been seen elsewhere, 1 each of the two 



1 Cf. Fig. 6, p. 61. 



