426 APPENDIX. 



{3) Bacillus pseudopneumonicus. — Very like the true bacillus of pneu- 

 monia ; but it has been found in pus taken from abscesses. The colonies 

 seen through the microscope are dark grey in colour, and finely granular ; 

 puncture cultures in gelatine have the characteristic nail appearance ; 

 grows rapidly, and differs from the two previous forms in that it causes 

 rather dark coloration of the gelatine, and gives rise to a slight putrefactive 

 odour ; grows well on potatoes as a white, viscid layer, but no gas is formed 

 even at a temperature of 37° C. Requires air for its growth ; micro- 

 scopically it is very like the pneumonia bacillus, 1. 16/< in length, and .9/t 

 in diameter. It is only slightly, if at all, pathogepic. 



/3. Colonies with smooth borders. 



(i) Bacillus oxytocus perniciosus. — Obtained from milk that had been 

 allowed to stand for a considerable time. Occurs on plate cultures as 

 small colonies, with smooth borders and circular outlines ; under the micro- 

 scope appears to have a light brown colour ; growing on the surface may 

 attain a size of 1.5 mm. ; colonies are.greyish white, and are usually round ; 

 needle cultures have, at first, the characteristic nail appearance but, 

 after a time, the growth along the needle track is comparatively small, 

 whilst the surface growth becomes very extensive ; gives a peculiar acid 

 reaction to milk but no odour is developed ; under the microscope it 

 is seen as a short rod with rounded ends, somewhat thicker and shorter 

 than the lactic acid bacillus. In large doses is fatal to rabbits. 



(2) Bacterium lactis alrogenes. — Found in the small intestine of mam- 

 mals and sometimes even in milk. Colonies have smooth borders ; 

 do not spread out much, but are usually of considerable thickness, like 

 little white porcelain points. In needle cultures it grows luxuriantly in 

 the nail form ; along the line of the needle, small rounded points occur at 

 regular intervals, so that the growth looks almost like a string of beads ; 

 forms white layers on potato, in which bubbles of gas are frequently 

 developed, sometimes this layer has a peculiar creamy appearance ; grows 

 rapidly at about 37° C. ; causes diarrhoea and collapse in rabbits and guineai- 

 pigs, but does not affect mice ; short thick rods with rounded ends I to Z\i. 

 long and .5 to .8/i broad ; usually occurs in pairs, or may be arranged in 

 irregular masses ; the organism is non-motile. 



(3) Weisser bacillus. — Obtained from water. Grows on gelatine plates 

 as round smooth white pin-head-like colonies ; in gelatine tubes it grows 

 slowly, forms a whitish mass along the track of the needle and a white 

 head on the surface ; on potatoes it forms a yellowish-white growth ; grows 

 slowly; the organism is a short motile bacillus with truncated ends, 

 often joined to form chains. 



d. Colonies are branched, not circumscribed. 



(1) Bacterium Zopfiii. — First found in the intestine of fowls. It grows 

 on plates almost like a mucor ; in needle cultures appears as a thick, pale, 

 yellow string, from which white branches radiate into the surrounding 

 gelatine; is strongly Eerobic, and grows very rapidly, especially at a 

 temperature of about 20° C. ; spores are formed which are extremely 

 resistant to heat ; the orgalnism is from 2 to S/i in length and from .7 to i/t 

 in breadth ; is motile ; occurs in long threads, which in gelatine show 

 numerous bends or spirals. 



(2) Bacillus of Mouse 6'«///r<«;«2a.— Originally found in garden earth and 



