SYSTEMATIC AND DESCRIPTIVE. 309 



METHODS OF STAINING HAY BACILLUS. 



To demonstrate the flagella of the bacilli, they may be 

 stained with haematoxylin solution (Koch). 



The linking together of cocci, long rods, and short rods 

 in the threads, is shown by treating with alcoholic solution 

 of fuchsine, or with iodine solution (Zopf). 



To stain the spores the cover-glass preparations must be 

 heated to a very high temperature (210 C.), in the hot-air 

 steriliser for half an hour, or they may be exposed for a 

 few seconds to the action of concentrated sulphuric acid 

 (Biichner), or floated for twenty minutes on hot solution of 

 the dye. 



Bacillus ulna, Cohn. Cocci, short rods, long- 

 rods, and threads. Diam. of the cocci 1*5 2*2 /x. 

 Spore-formation in both short and long rods. No 

 septic odour is produced by this bacillus in a 

 nourishing liquid. Cloudy masses are found on the 

 surface of the liquid, which later form a thick dry 

 pellicle. The latter consists of bundles of threads 

 matted together. The formation of ellipsoidal 

 spores occurs in the usual way ; they measure 

 2 '5 2*8 /x long, and more than i /* wide. The 

 bacillus is found in rotting eggs, and can be culti- 

 vated on boiled white of egg. It is closely allied 

 to Bacillus subtilis. 



Bacillus tumescens, Zopf.* Cocci, long and 

 short rods. They form a jelly-like disc, '5 i cm. 

 in diam., on slices of boiled carrot, with the appear- 

 ance of a rather tough crumpled skin of a whitish 

 colour. Examination of this pellicle shows that it 



* Zopf, Die Spaltpilze. 1885. 



