84 THE DISEASES OF DOMESTIC ANIMALS. 



single cell, or of two, three, or more segments. Thickness im- 

 measurable ; well-defined flexible movement of an active or passive 

 character. Reproduction is by fission and by globular or oval 

 spores, which develop in the interior of the articulations. They 

 are to be found in stagnant waters. 



This bacillus plays an important part in butyric fermentation. 

 It exists in rennet, and can support a temperature of 105° C. and 

 live in a medium deprived of pure oxygen, in which case it takes a 

 peculiar form and contains persistent spores which when set free 

 give rise to other rods. 



Bacillus anthracis is a species very similar to the preceding, but 

 generally longer, and always motionless ; length four, twelve, and 

 even fifty micrometers ; thickness scarcely measurable. 



Bacillus anthracis is developed in charbon — carbuncle — of cattle, 

 man, sheep, horse, rabbit, rat, etc. ; never in dogs, the cat, birds, and 

 cold-blooded animals. It is found, above all, in the capillary vessels. 

 When cultivated in suitable media, such as the aqueous humor of 

 the eye of the ox, and the different cultivation fluids, this bacillus 

 develops spores in the interior of its segments w r hich may germinate 

 and develop rods. 



The other bacilli of this group are without any special interest. 



The only form of special interest is the " spirochaeton hermeieri," 

 found in the blood of persons suffering from recurrent fever (chills 

 and fever), but only during the access, never during the intermis- 

 sions of the disease. 



Distinction of Bacteria from Inorganic Substances. 



No one has ever questioned the living nature of bacteria, except 

 with reference to the most invisible varieties. These smaller forms 

 may be often confounded with various matters, such as organic par- 

 ticles, molecular granules, fat-globules, or fatty detritus. To distin- 

 guish them from micrococci is almost impossible, unless the greatest 

 circumspection is taken by the observer. 



The detritus, or the amorphous powder, or precipitated mole- 

 cules, of inorganic substances, though they equally well exhibit the 

 noted Brownian movement, are to be distinguished from micrococci 

 by such optical signs as their angular or irregular form, their lesser 

 refraction, and their action toward certain chemical agents. 



The case is quite different if the molecules are of an organic 

 nature. They enjoy, in common with micrococci, a round form, 

 movement, and refraction. However, their form is wanting in the 

 regularity proper to germs ; they vary in color, and their refractive 



