22 PHARMACEUTICAL BACTERIOLOGY. 



few of the philosophical biologists, as Ernst Haeckel, place them in a separate 

 group, the Monera, which is supposed to form the connecting link between 

 plants and animals. 



Without entering into lengthy discussion, we shall, in conformity with the 

 opinion of the majority, class them as plants, belonging to the lowest of the 

 group fungi (the fungi includes rust, smuts, cup fungi, moulds, spot fungi, 

 toad-stools, etc.), namely, the Schizomycetes or fission fungi, so called because 

 they multiply by fission or division. They are related to the yeasts, though 

 somewhat lower in the scale of evolution. They are single-celled, each cell 

 forming a complete living unit, though the several units may be variously 

 arranged into chains or clusters or groups known as zoogolea. 



The scientific grouping of microbes is as yet very unsatisfactory because 

 so little is known of their ultimate morphology, their physiology and chemis- 

 try. Some have attempted to classify them as to form, others as to occur- 

 rence, as to action, etc. Thus, we have: 



a. Micrococci or Coccaceae. Globular or non-elongated microbes. 



b. Bacilli or Bacteriaceae. Cells more or less elongated. Rod-shaped 

 microbes. 



c. Spirillae or Spirillaceae. Cells elongated and more or less spirally 

 twisted. Or, we may have: 



a. Bacteria of earth. 



b. Bacteria of air. 



c. Bacteria of water. 

 Or, again: 



a. Chromogenic. 



b. Zymogenic. 



c. Pathogenic, etc. 



These artificial groupings could be extended indefinitely, but such sys- 

 tems of classification would be as unsatisfactory as they are unscientific. The 

 best system makes use of all of the known facts of bacteriology. Several such 

 systems have been proposed from time to time, but the new discoveries along 

 bacteriological lines make it necessary to change them in the course of two or 

 three years. Migula, Fischer, Eisenberg and others have proposed general 

 systems, and a host of investigators have submitted more limited group sys- 

 tems. The following classification will serve to convey some idea as to the 

 structural characteristics of the more important groups: 



BACTERIA OR MICROBES. 



(Schizomycetes or Fission Fungi.) 



I. Family COCCACEAE. Micrococci. Cells globular or not elongated. 

 Division in two or three directions of space. Spore formation rare. 



