74 THE BEGINNINGS OF LIFE. 



was, in 1836, definitely compared by Schwann to the 

 formation of crystals. Cells, which were then believed 

 to be the types of all rudimentary organisms, were 

 thought by him to owe their form to a process essen- 

 tially similar to crystallization ; the characteristic shapes 

 being due, in the case of cells, to a peculiarity in the 

 nature of the substance of which they were composed. 

 As Schwann expresses it : c The formation of the ele- 

 mentary shapes of organisms is but a crystallization 

 of a substance capable of imbibition. The organism is 

 but an aggregate of such imbibing crystals V But 

 as may have been gathered from statements already 

 made, Mr. Herbert Spencer has, within the last few 

 years, much more fully worked out the doctrine that 

 the structures and shapes of organisms are the results 

 of the c polarities' of their constituent organic units, 

 under the continually modifying influence of external 

 conditions 2 . To his full and admirable treatment of 



1 A doctrine somewhat similar to Schwann's has been more recently 

 advocated by Dr. Montgomery. He sums up a memoir published in 

 1867, 'On the Formation of so-called Cells in Animal Bodies,' with 

 these words : ' The experiments which I have communicated go a 

 good way to show that a plastic imbibing material driven into 

 individual shapes by a crystallizing influence is the cause of " cell " 

 formation.' 



2 See more especially the Appendix to his ' Principles of Biology.' In 

 the work itself he appeared to lay too much stress upon ' inherent 

 tendencies,' and this has given rise to adverse criticisms. In the 

 Appendix, Mr. Spencer admits that he did not 'adequately explain' that 

 ' the proclivity of units of each order toward the specific arrangement 

 seen in the organism they form, is not to be understood as resulting 



