xvn MYSTERY OF THE CELL 349 



mass of bony matter, covered with a thin skin and dense 

 hair, is rapidly built up to a very definite form in each 

 species ; then the skin and hair cease growing and fall away, 

 while the horns persist for nearly a year, when they, too, fall 

 off and are again renewed. 



Concluding Remarks on the Cell-Problem 



The very short account I have now given of what is 

 known of the essential nature, the complex structure, and 

 the altogether incomprehensible energies of these minute 

 unit-masses of living matter, the cells so far as possible in 

 the very words of some of the most recent authorities 

 must, I think, convince the reader that the persistent 

 attempts made by Haeckel and Verworn to minimise their 

 marvellous powers as mere results of their complex chemical 

 constitution, are wholly unavailing. They are mere verbal 

 assertions which prove nothing ; while they afford no 

 enlightenment whatever as to the actual causes at work in 

 the cells leading to nutrition, to growth, and to reproduction. 



Very few of the workers who have made known to us 

 the strange phenomena of cell-life in the Protozoa, and of 

 cell-division in the higher animals and plants, seem to think 

 anything about the hidden causes and forces at work. They 

 are so intensely interested in their discoveries, and in 

 following out the various changes in all their ramifications, 

 that they have no time and little inclination to do more than 

 add continually to their knowledge of the facts. And if 

 one attempts to read through any good text-book such as 

 Parker and Haswell's Zoology, or J. Arthur Thomson's 

 Heredity, it is easy to understand this. The complexities 

 of the lower forms of life are so overwhelming and their 

 life-histories so mysterious, and yet they have so much in 

 common, and so many cross-affinities among the innumerable 

 new or rare species continually being discovered, that life is 

 not long enough to investigate the structure of more than a 

 very small number of the known forms. Hence very few of 

 the writers of such books express any opinion on those 

 fundamental problems which Haeckel and his followers 

 declare to have been solved by them. All questions of 

 antecedent purpose, of design in the course of development. 



