474 BACTERIOLOGIC TECHNIC. 



fever. It is strikingly motile, always in the blood, and 

 grows anaerobically. Both in the blood and in cultures 

 many, but not all, of the individuals present one or two 

 very long, motile, spiral appendages, which take the stain 

 for flagella. Lewaschoff calls this form of remarkable 

 spirochete, exanthematica. According to his opinion, 

 there is perfect agreement between his findings and the 

 newer investigations of LjubimofT (cocci), Calmette and 

 Thoinot (A. P., 1892, 39) (egg-shaped bodies and spirilla), 

 von Dubief and Bruhl (C. B. xiv, 17), Curtis, and Combe- 

 male (diplococci). 



APPENDIX IV. 



Essentials of Bacteriologic Technic. 



The following directions and short explanations include about all 

 the technical material which is given in a thorough bacteriologic 

 course. We have introduced only those things which are essential 

 and, according to our experience, practical, without referring to the 

 literature. More details will be found in the books mentioned in the 

 preface. 



I. Microscopic Examination of Bacteria. 



i. Hints upon Microscopic Technic. 



For bacteriologic examination we use almost exclusively the modern 

 microscope with Abbe's illuminating apparatus, iris diaphragm, and a 

 low-power and an oil-immersion objective. 



(A) Low magnification (6o to ioo times) with a narrow dia- 

 phragm is used in the minute examination of plate cultures. In this 

 examination either the cover 1 is removed and the colony examined 

 from above, or, if one does not wish to contaminate the plate by expos- 

 ing it, the dish is laid upon the cover and the colony examined from 

 below, but this does not give such characteristic pictures in all cases. 



(B) High Magnification. ()il=immersion Objective ( 700 to 

 1200 times). — This finds its use in the examination of single indi- 

 viduals. A drop of cedar oil is placed upon the preparation (slide, 

 cover-glass) and the tube is lowered by means of the coarse adjust- 



1 Our plate cultures are always poured into dishes. 



