302 Prof. E. Boyce and Mr. A. E. Evans. 



twisted forms ; the degree of spirillation in the latter motile forms, 

 however, appears only very slight, and we have not, as yet, encoun- 

 tered the pronounced spirilla seen in Gladothrix. It occurs in iion- 

 motile filaments of great length, which may be unsegmented or seg- 

 mented. A very striking feature of these filaments is their proneness 

 to twist, to weave themselves into striking patterns, and to form 

 aggregating zoogleaform masses, of equally curious shapes. The 

 segments of the filaments may occur in the form of cocci, bacteria, 

 bacilli, vibrios, spirilla, and spirochsetoB and in the various double 

 forms of these. Kurth grew the organism in broth and on gelatine, 

 and obtained in the former the motile and long filamentous forms, 

 whilst the twisted varieties appeared wanting : this we likewise have 

 noted. In gelatine he found that it caused an imperceptible amount 

 of liquefaction and grew out in a radiate manner, and formed charac- 

 teristic spirals. Crookshank grew it upon agar, and obtained a 

 feather-like growth which he figures ; this, however, we have always 

 failed to obtain upon that medium. Kurth drew attention to the 

 sensitiveness of the organism to changes in temperature, to the 

 hindering action of the air, and to the great necessity for plenty of 

 oxygen. 



yAe Growtli of Bacterium Zopfii upon Gelatine. 



For our experiments we have always employed the 10 per cent, 

 gelatine possessing a neutral or faintly alkaline reaction, but we have 

 found no appreciable difference whether the organism was grown on 

 gelatine with faintly alkaline or acidic reactions. We use the ordinary 

 culture-tubes, Petri boxes, and a method of plate glass culture which 

 we have found exceptionally useful. This method consists in placing 

 a small piece of moist cotton wool in the bottom of a test-tube large 

 enough to hold the ordinary 1x3 inch micro-slide ; the test-tube is 

 plugged, and the whole sterilised in the steam steriliser at 120 for 

 20 minutes. When cooled, a thin uniform layer of sterilised gelatine 

 is very readily spread over the surface of the slide in the test-tube, 

 which remains horizontal, by means of the balloon pipette of Pasteur : 

 there is no fear of contamination. The test-tube is plugged and 

 capped to prevent drying, and the slide is then always ready for 

 inoculation. When a streak culture has been made upon the gelatine 

 surface, and it is desired to examine the growth, the slide is removed 

 and placed in slightly diluted spirit for a few hours, to fix the growth 

 and extract the salts. The slide is then carefully dried, stained for a 

 few seconds in gentian violet, washed with Gram's iodine, and nearly 

 decolorised in spirit, again dried, mounted in Canada balsam, and 

 covered with a sufficiently long cover-slip. By this method there 

 is the least possible disturbance of the growth,^ and all our micro- 



