CELLS NOT LIKE BRICKS. 55 



until the fully developed structure results, will be careful 

 not to accept without due consideration the vague generali- 

 sations of those who persist in authoritatively declaring that 

 the changes occurring in cell growth are merely mechanical 

 and chemical, although they are unable to produce by any 

 means at their disposal a particle of fibrine, a piece of carti- 

 lage, or even a fragment of coral. They avoid the difficulty 

 as regards the germinal matter by ignoring its existence, and 

 attribute to a " molecular machinery" which the mind cannot 

 conceive, and which cannot be rendered evident to the 

 senses, all those wonderful phenomena which are really due 

 to vital power. Moreover, resemblances to living organisms 

 of the most fanciful kind are adduced apparently for the 

 purpose of leading people to believe that non-living matter 

 behaves like that which is alive.* 



On the Nutrition of a L iving Cell. 



In nutrition, the active changes are exclusively confined 

 to the germinal matter. The formed material is passive, 



* Professor Tyndall describes (Proceedings of the Royal Society, 

 vol. xvii, No. 105) the changes resulting from the influence of light on 

 the vapour of an aqueous solution of hydriodic acid. His rhapsodical 

 description, which extends over an entire page, contains the following 

 curious allusions and comparisons : A cloud was developed like an 

 organism from a formless mass to a marvellously complex structure ; 

 spectral cones with filmy drapery ; exquisite vases with the faintest 

 clouds, like spectral sheets of liquid, falling over their edges ; clouds 

 like roses, tulips, sunflowers, and bottles one within the other ; a cloud 

 like a fish, with eyes, gills, and feelers, and like a jelly fish, with the 

 internal economy of a highly complex organism, exhibiting the twoness 

 of the animal form ; as perfect as if it had been turned in a lathe ; and 

 likely to prove exceedingly valuable to pattern designers ! 



