84 Hte TOL OG Y OF NUTRIENT FL UIDS. 



condenser. The staining is done by spreading a layer of the 

 blood, sputum, etc., between two thin covers, separating the cov- 

 ers, and passing them rapidly through the flame to coagulate 

 the albumen. They are then stained with some of the aniline 

 dyes and the excess of stain removed by water or alcohol- 

 Sometimes a contrast stain of some other color is used. 

 Some kinds of bacteria are more difficult to demonstrate than 

 others, and tissue sections more difficult than fluids. The de- 

 tails of technology must be referred to the intermediate course. 



Bacteria was a term formerly appropriated to bacilli, but is 

 now used generically. They may be classed according to form 

 into micrococci, bacilli, and spirilla. The microcci are spheri- 

 cal or oval. They may occur singly or in groups. Chains of 

 cocci are called streptococci, those forming irregular clusters 

 staphylococci, double ones are diplococci, and groups of four, 

 tetragoni. Sometimes groups of four, sixteen, etc., are seen 

 resembling packets bound with cords at right angles; these 

 are termed sarciruz. The bacilli are rod shaped, and sometimes 

 occur in chains called leptothrix. Some bacilli are constricted 

 in the middle, or dumb-bell shaped, and others are rods with 

 parallel sides and rounded, square, or concave ends. Bacilli 

 which are curved on the long axis are called commas, or com- 

 mabacilli, and a chain of them forms a spirobactcrium or spiril- 

 lum. Fig. 6, PL 3. 



Pathogenic cocci, i. The cocci of pus. (i) Staphylococcus 

 pyogenes aureus. (2) Staphylococcus pyogenes salivarius 



(3) Streptococcus pyogenes. (4) Streptococcus septo-pyaemi- 

 cus. (5) Streptococcus salivarius septicus. (6) Streptococcus 

 pyogenes malignus. (7) Streptococcus articularum. (8) Mi- 

 crococcus pyogenes tenuis. (9) Micrococcus gonorrhoea gon- 

 ococcus. This is a diplococcus, sometimes in groups of four. 

 (10) Micrococcus subflavus. (i i) M, tetragenus. (12) M. Pas- 

 teuri (found in saliva of healthy persons, produces septicaemia 

 in rabbits). 



Pathogenic bacilli, (i) Bacillus anthracis. (2) B. aedema- 

 tis maligni. (3) B. of symptomatic anthrax-rauschbrand. 



(4) B. typhic abdominalis. (5) B. pneumoniae-pneumococ- 

 cus. (6) B. tuberculosis (considered the origin of tuberculo- 



