MORAX-AXENFELD BACILLUS 461 
Resistance.— The Koch-Weeks bacilhis is very susceptible to rlryint]; 
and to heat; chemical disinfectants very rapidly destroy the organism 
outside the human body. 
Nothing is known of the products of growth. 
Pathogenesis.— Attempts to produce conjunctivitis in animals with 
the organism have been uniformly negative, but inoculations upon the 
healthy conjunctiva of man usually reproduce the disease. Weich- 
selbaum and ]\luller^ discovered that fresh material from the eye 
induced a typical infection W'hen rubbed upon a human cornea, but 
the same material dried at room temperature for eight hours was 
incapable of inducing a corneal infection. 
The disease is very contagious; it is spread chiefly by contact. Care- 
fully destroying the purulent exudate prevents the spread of the dis- 
ease. Patients should be isolated and cared for by specially trained 
attendants whenever possible. 
THE MORAX-AXENFELD BACILLUS. 
In 1S9() ^lorax- described a diplol)acillus which he observed repeat- 
edly during an epidemic of subacute conjunctivitis. The year follow- 
ing, Axenfeld^ published an excellent description of the same organism, 
which is commonly referred to as the Morax-Axenfeld bacillus or the 
diplobacillus of subacute conjunctivitis. 
Morphology.— The organisms, as the name implies, occur typically 
in pairs; less frequently they may remain adherent to form short 
chains. The individual bacilli are of medium size, measuring from 
1 to 2 microns in length, and about 1 micron in diameter as an average. 
The ends of the bacilli are rather square cut. C\iltures on artificial 
media are somewhat variable in size and shape; chain formation is not 
uncommon and involution forms are frequent. The organisms are 
non-motile and possess no flagella. Neither spores nor capsules have 
been demonstrated. Ordinary anilin dyes color the bacilli readily, 
and the Gram stain is negative. 
Isolation and Culture. — Growth occurs only in media containing 
bloofl scrum or ascitic fluid; LoflKer's alkaline blood serum is a favorable 
substrate. The colonies on blood serum after twenty-four to forty- 
eight hours' development at 37° C. are slightly sunken, due to the 
liquefaction of the medium. After several days the serum is almost 
completely liquefied. Colonies grown on ascitic agar are small, color- 
less and trans])arent even after several days' incubation. Oxygen 
is essential for the growth of the bacilli; no growth occurs when oxygen 
is excluded frf)m the media. 
Products of Growth.— A proteolytic enzyme which li(iuefies coagu- 
lated blood seriun is the only enzyme which has been described. No 
other products of growth are known. 
1 Arch. f. Ophthalmol., 1899, 47, 108. 2 Ann. Inst. Pasteur, 1896, 10, .337. 
••' Centralbl. f. Bakteriol., 189', 21, 1. 
