PLATE IH-BACTERIUM ANTHRACIS, or BACILLUS ANTHRACIS, COHN. 



(A/ler Dodel-Port.) 



Splenic Fever Bacterium, or Bacillus Anthracis (Lat bacillum, a little staff; anthrax, anthracis, coal), may be taken as the type of 

 those contagious disease germs which have been so destructive in their effects upon the human race, and which are only now being care- 

 fully studied The principal facts made out concerning it may serve as a guide to other forms. It is interesting to note that it has 

 been made to lose its infecting power by frequently changing it in a solution of extract of meat ; and one of the triumphs of science at 

 the present day has been to render this and such-like deadly organisms comparatively harmless, by appropriate treatment The minute 

 size and immense numbers of the spores readily explain the spread of the infection, and as it has been proved that they may retain 

 their vitality for years, the disease may break out quite unexpectedly. It is also matter of experimental proof that the fever ensues 

 when the germs are taken in with the air breathed in the form of a dry dust, and thus reach the blood in the Lungs; or they may 

 reach the blood through scratches or other means. 



Figures X 3000. 



Pig. 1. Transparent rods, straight and bent, and of various lengths. 



These rods are colourless and motionless. They divide transversely, and the joints adhere to form longer or 

 shorter rods. 



Fig. 2. Filament produced by the elongation of the rods. 



These filaments may attain a length several hundred times that of the original rods, and when fully developed, 

 their contents break up into numberless spores or endogonidia 



Figs. 3 and 4. Spores placed obliquely or perpendicular to the long axis of the filament 



The spores are oval or elliptical, with highly refractive contents and a dark outline. 



Fig. 5. Gelatinous scum containing spores arranged in rows. 



The gelatinous material gradually dissolves in the water, thus setting the spores free. 



Fig. 6. Clusters of spores set free — either as above, or by the deliquescence of a gelatinous filament 



Fig. 7. Development 



(a.) Oval spore. 



(b.) Oval spore, lengthening and dividing. 



(<:.) Short rod lengthening and dividing further. 



\d.) Longer rods formed. 



(e.) Long jointed rod, as in Fig. i. 



Life History. — The original short rods grow and lengthen in an appropriate medium, such as blood-serum or the aqueous humour 

 of the eye. The filaments, thus produced, having attained their full development soon begin to show in their interior 

 numerous bright spots, which latterly become the spores, and the rest of the filament passes into a jelly-like mass. 

 Several of the filaments may lay themselves together and so produce a gelatinous scum with the spores embedded and 

 arranged in rows. The spores are set free by the dissolution of this gelatinous material, and are then ready to begin 

 anew their course of development. 



