DIATOMS- CONGER 331 



diatoms that live habitually floating in the open sea, where, at the 

 same time, silica is less abundant. However, those diatoms that live 

 attached, where the continual wash of water brings to them an abund- 

 ant supply of the necessary substances for growth, can produce either 

 heavier shells or a very luxurious growth within a small area, and 

 along the bottom, nearer the source of silica, live the heavier, larger 

 diatoms Avith a massive type of shell structure, indicating an ample 

 supply of structural material. (Pis. 5 and 6.) 



Why diatoms are so infinitely multiplied and diversified to all con- 

 ceivable shapes and patterns, when a few types of shell structure 

 could probably fulfill their purposes and needs, is an evolutionary 

 and philosophical question which applies to other life forms as well 

 and which has not yet been answered. One might as well inquire 

 why man has not deliberately planned a model house incorporating 

 all practical features of comfort and convenience, and having once 

 designed this model house, busied himself with building a world 

 full of these houses for all men to live in ; but many different indi- 

 viduals develop as many diverse ideas of structure and design. 



It is interesting to see in a group of such minute forms as the 

 diatoms so perfect an application of the same principles and de- 

 vices as are found in larger forms and as have been made use of in 

 many ways in the works of man. Throughout the group of diatoms, 

 their shells seem to embody the elements of fine structural engineer- 

 ing, together with principles of architectural design adapting them 

 to their types of abode and to the necessities of their various modes 

 of existence. All features of their shell designs seem to center about 

 and be controlled by these purposes, which contribute largely to the 

 great diversity and beauty of design and incidentally to their wide 

 industrial application, as we shall see. 



The whole history of civilization, of man's exploitation of material 

 and subjection and control of energy resources in his attempt to 

 establish his domain over nature, has shown a steady trend toward 

 an understanding and manipulation of the finer and ever finer 

 forces and conditions of nature. So it is that small things which 

 have seemed of little or no importance have come one by one to 

 take prominent places on the stage of human interest, and the oft- 

 repeated question, "What is it good for?" promises eventually to be 

 answered for every natural substance. 



The renowned biologist Lamarck has said (Philosophic Zoolog- 

 ique) : "The most important discoveries of the laws, methods, and 

 progress of nature have nearly always sprung from the examination 

 of the smallest objects which she contains, and from apparently the 

 most insignificant enquiries." The late Theobald Smith is quoted 

 (Simon Henry Gage, Science, vol. 84, no. 2171, Aug. 7, 1936, p. 



