206 BACTERIOLOGICAL OBSERVATIONS MADE AT LITTLE BAY, 



form loose, somewhat visible vegetations, easily removable from the 

 potato-surface. For such small deviations the quality of the used 

 potatoes is made responsible; but it must also be borne in mind that 

 the least possible quantities of seed material should be taken with 

 which to sow potato-slices. Similar deviations have come under 

 my notice, yet in all such cases it cannot be difficult to arrive at a 

 correct diagnosis, if, besides also all the other features exhibited by 

 typhoid-bacilli, microscopical appeai'ances, characters of cultures, 

 and staining reactions, are duly considered. 



Quite recently Fraenkel and Simmonds have furnished some 

 more data as to the cultivation of the typhoid-bacilli on potatoes ; 

 these remarks seem to me to be sufficientl}? worthy of note that I give 

 here a complete translation of them. They say (Zeitschrift f. 

 Hygiene, Band II., Heft 1, Leipzig, 1887, pp. 140-141) :— 

 " . . . . In continuing our investigations into the typhoid- 

 bacillus, other far more important deviations have come under our 

 notice, deviations which in the beginning made the purity of our 

 culture appear doubtful to us. Sometimes when we had inoculated 

 numerous potato-surfaces from one gelatine-culture at the same 

 time, it happened that after three or four days some surfaces 

 showed a quite peculiar appearance, besides other normal-looking 

 potato-surfaces. There was on the surface an easily recognisable, 

 grey, viscous coating, the margins of which were very distinctly 

 visible. At those places which were not sown the potato 

 exhibited a brownish colour, and the older the culture grew, the 

 darker became the colour of the parenchym. No smell whatever 

 w&s perceptible. On examination the normal-looking potato- 

 surfaces were found to contain magnificent specimens of typhoid- 

 bacilli with preference arranged in pseudo-filaments. The 

 examination of the grey, viscous, easily removable cultures of the 

 rest of the potatoes yielded, as result, the presence of an infinitely 

 larger quantity of bacilli, yet these were so far behind their usual 

 length and thickness that undoubtedly every observer, especially 



