208 BACTERIOLOGY 



its birth to a chemist, that concerns itself with microscopic organisms 

 belonging both to the plant and animal kingdoms, and that extends 

 its ramifying branches into the regions of medicine, hygiene, and the 

 industrial arts. 



In several respects the history of bacteriology might be held to 

 epitomize that of the other natural sciences, or of the living organism 

 itself. Advance in complexity of structure entails greater complex- 

 ity of relations and adjustment; maturity has more extensive 

 connotations than youth. Bacteriology is a relatively youthful 

 branch of the stream of knowledge, but in late years it has per- 

 ceptibly widened its banks. It has even encroached upon certain 

 neighboring sciences. Modern physiography uses the term piracy 

 to designate the capture by one stream of that portion of a water- 

 shed legitimately belonging to another stream. In the same way, 

 one natural science, owing to peculiarities in its subject-matter, in 

 its evolutionary history, or in the tools with which it works, may 

 enter upon a piratic career, and appropriate territory which for va- 

 rious reasons has remained unexploited by the science to which 

 topographically it may seem to belong. This annexation of neigh- 

 boring fields has been not uncommon among the natural sciences, 

 and bacteriology has not shown itself free from the general tend- 

 ency. A notorious instance of piratic conduct on the part of bac- 

 teriology is the virtual appropriation of the whole field of micro- 

 biology. Perhaps most familiar in this connection are the discoveries 

 concerning the life-histories of various microscopic animal para- 

 sites. The tracing-out of the relations between parasites and hosts 

 in Texas fever, malaria, and dysentery has by no means been ex- 

 clusively or even largely the work of zoologists. On the contrary, 

 it is well known that much of the most important work in this 

 direction has been carried out by bacteriologists, and that the lit- 

 erature on these topics is chiefly to be found in the technical bac- 

 teriologic journals. A recent instance of this tendency is the renewed 

 study of the remarkable protozoa called trypanosomes, which has 

 in large part been undertaken by bacteriologists and by bacterio- 

 logic methods. Perhaps the most notable triumph yet accomplished 

 in this field is the successful cultivation of these pathogenic protozoa 

 outside of the animal body, a feat which has been achieved by one 

 of the foremost American bacteriologists. The exploitation of zoo- 

 logic territory by bacteriologic workers is one of the many instances 

 of successful borderland invasion, and, like the Louisiana Purchase, 

 illustrates the impotence of territorial lines to prevent natural ex- 

 pansion. Many reciprocal piratic inroads among the sciences are 

 due to the acquisition by one science of new tools which, when 

 workers become generally acquainted with their use, are found to 

 be applicable to other problems in other fields. Bacteriologic 



