E. M. DoiDCxE 67 



No capsules liave been observed around rods within the tissues 

 of the host. 



Tlie capsule around each rod in an impression preparation stained 

 with fuchsin measures rougjily 1-5 /x in diameter and it exceeds the rod 

 in length by about -O/x at each end. A few rods may be seen without 

 capsules and empty capsules are quite common, but it was not clear 

 whether the rods escape from the capsules or whether they had been 

 torn away in making the preparation, 



Involulion forms were observed in broth cultures containing high 

 percentages of sodium chloride. They are very common in 48 hour 

 old cultures in broth containing 9-5 per cent, to 10-5 per cent. NaCl. 

 The rods comparatively are very large, some grow out into filaments 

 as much as 100 ju, long, and they are irregularly swollen and contorted 

 in every direction (Plate XIII, e). Quite a number are club-shaped. 

 They stain intensely vnih. aniline gentian violet and when transferred 

 to ordinary nutrient broth rapidly divide and produce rods of normal 

 form. 



Aberrant forms are also found in old potato cultures. A smear 

 made from a 12 days old potato culture consists of very minute intensely 

 staining capsuled forms, some of which are almost spherical and 

 slightly swollen rods of normal length which stain very feebly or 

 irregularly. The latter were only faintly stained in half-an-hour by 

 carbol gentian violet (Plate XIII, 6). 



Staining reactions. The bacillus stains well by all the ordinary 

 methods, but varies considerably in its reaction to the various dyes. 

 In testing the action of the different stains smears were made from 

 a 24 hour old streak on nutrient agar. Dilute aqueous solutions were 

 allowed to act for two minutes ; in this time the thionine and methylene 

 blue hardly stained the rods at all, fuchsin gave a distinct though 

 rather faint coloration and the rods stained with gentian violet were 

 very intensely and quite sharply stained. Carbol gentian violet also 

 gave a very strong intense stain in half a minute and brought out the 

 capsules which were not stained by the aqueous solution. Ziehl's 

 carbol fuchsin gave a similar result ; carbol methylene blue and carbol 

 thionine also stained very faintly in half a minute, but Loeffler's blue 

 gave much better results in the same time though not nearly so intense 

 a stain as the gentian violet and fuchsin. 



The organism is (i ram-positive, and stains blue by the Ziehl Neelson 

 method, i.e., it is not acid fast. 



Spores. No spores have been observed. 



