DESCRIPTION OF PLATE. 



The figures iu the plate are to illustrate the flagella on these three 

 species of bacteria as they appeared in stained cover-glass preparations. 

 The drawings were made by the aid of a Zeiss apochromatic objective, 

 2 mm., 1.30 n. a. and the measurements were made with the com- 

 pensating micrometer ocular No. 6. Each germ and its flagella were 

 carefully measured and in the drawings each micromillimetre is rep- 

 reseuted by a millimeter, thus giving a magnification of a thousand di- 

 ameters. The curves in the flagella were carefully counted and repro- 

 duced as accurately as it was possible by freehand drawing. The posi- 

 tion of the flagella was also carefully determined. In the preparation 

 of the plate care has been taken to avoid extremes. Individual bacteria ' 

 have been selected from different fields to represent the various number, 

 lengths and position of the filaments on the body of the germs as they 

 appeared in the preparations. A few free, or detached flagella are also 

 indicated. The drawing of each germ is practically equivalent to a photo- 

 graph. It is possible to fiind all of the structures represented in a few 

 fields of the microscope in a well executed preparation. The germ in 

 the center of each figure represents the maximum number of flagella on 

 a single individual. In the left lower corner of each is a drawing of a 

 clump of bacteria with their flagella. There are a few drawings of bac- 

 teria (a) with only their periphery and flagella stained. 



Fig. I. BacilUts cholercF suis. Drawings made from preparations of 

 the culture of hog cholera bacteria obtained in the State of Illinois, (b) 

 A bunch or strand of flagella. 



Fig. 2. Bacillus coli communis. Drawings made from preparations 

 from the culture obtained from the human intestine. 



Fig. 3. Bacillus typhi abdominalis. Drawings made from prepara- 

 tions of the typhoid bacillus which was obtained from the Johns Hopkins 

 Hospital. The upper right hand corner, enclosed in dotted lines, rep- 

 resents all of the bacteria and flagella from a single microscopic field. 



