ZOOLOGICAL -NOMENCLATURE. I 7 1 



a suitable habitat and in return protects its host against strictly 

 pathogenic bacteria. 



3. Commensalism. Here there is benefit to the parasite, but no 

 injury to the host. An example of this kind would be furnished in the 

 case of the Trichomonas vaginalis which lives in the vaginal mucus, 

 but, so far as known, does no injury to the host. 



4. Nomenclature. When the thousands of different species, genera, 

 etc., of animals is considered, it will be readily perceived that, 

 unless some system existed for their designation, indescribable con- 

 fusion would prevail. To avoid this, the International Code, based on 

 the rules of Linnaeus (1751), requires Latin or Latinized names. 

 There are certain rules governing the naming of animals. Of these, 

 the law of priority provides that the oldest name, under the code, of 

 any genus or species is its proper zoological name. The history of the 

 naming of the organism of syphilis illustrates this well. Schaudinn 

 gave this organism in 1905 the name of Spirochaeta pallida. Ehren- 

 burg, in 1838, had used the name Spirochaeta for animals of a different 

 character, so that this designation of the genus was not permissible 

 under the code. Villemin, a little later, proposed the name of Spiro- 

 nema. This term, however, was found to have been used in 1864. 

 Consequently it was not available. Stiles then proposed the name 

 Microspironema but as Schaudinn only about two weeks before had 

 offered the designation Treponema, the name Treponema pallidum 

 had to be accepted as the proper zoological name for the organism of 

 syphilis. 



Another point is that names are not definitions, consequently the 

 fact of lack of appropriateness of any name is no objection to its con- 

 tinuation. This will appeal to anyone as a wise provision, because if a 

 different name were substituted each time a designation more descrip- 

 tive or applicable were invented it would be utterly destructive to 

 system. When it is considered that some of our parasites have approxi- 

 mately 50 different designations, for the most part given by medical 

 observers, it will be appreciated how much the zoologist has aided us 

 in trying to eliminate all but the single proper zoological name. 



The objections so frequently heard among physicians in connection 

 with adopting new names for old ones are not well founded. Wher- 



