THE RELATIONS OF BACTERIOLOGY 209 



technique is one of these efficient tools the possession of which con- 

 duces to piracy; it can, however, never be forgotten that bacterio- 

 logy itself owes its powerful equipment to a study of spontaneous 

 generation which was undertaken primarily for the interest felt in 

 its philosophic bearings. 



Bacteriology stands in close relation to at least four other more 

 or less defined fields of natural knowledge: to medicine, to hygiene, 

 to various agricultural and industrial operations and pursuits, and 

 to biology proper. Bacteriology, as has been often said, is the 

 youngest of the biologic sciences, and for this reason has as yet con- 

 tributed relatively little to the enrichment of the parent science. 

 Morphologically the bacterial cell is so small and so simple as to 

 offer many problems of surpassing interest, but of great difficulty. 

 The question as to whether a bacterium is a cell without a nucleus, 

 or a free nucleus without any cytoplasm, or a cell constituted in the 

 main like those of the higher forms of life, has, to be sure, been 

 practically settled in favor of the latter view. But there are other 

 debated and debatable morphologic questions to which up to the 

 present no satisfactory answer has been given, and to which our 

 current microchemic methods are perhaps unlikely to afford any 

 solution. On the physiologic side, the achievements of bacteriology 

 in behalf of general biology have as yet been far from commensurate 

 with its potentiality. This may be partly because of its temporary 

 engrossment in other seductive lines of research, partly because of 

 the lack of workers adequately trained in bacteriologic methods and 

 at the same time possessed of an appreciation of purely biologic 

 data. It may be justly urged that a rich harvest of fundamental 

 physiologic facts waits here for the competent investigator. 



There is no need to dwell in detail upon the manifold practical 

 applications of bacteriology to the arts and industries. Particularly 

 in agriculture and kindred occupations have the advances in bac- 

 teriology been immediately and intelligently utilized to bring forth 

 in turn new facts and unveil new problems. The processes of cream- 

 ripening and vinegar-making, the phenomena of nitrification, of 

 denitrification and nitrogen fixation, the modes of causation of 

 certain diseases of domestic plants and animals, have all been 

 elucidated in large measure by bacteriologic workers. A new di- 

 vision of technologic science, dealing with the bacteriology of the 

 soil, of the dairy, and of the barnyard, of the tan-pit and the canning- 

 factory, has already assumed economic and scientific importance. 



It is often a temptation to distinguish radically between pure 

 science and applied science and to look upon the latter as unworthy 

 the attention of the philosophically minded. True science can admit 

 of no such distinction. Nothing in nature is alien to her. She can 

 never forget that some of the most fruitful of scientific theories have 



