234 ORGANISMS FOUND IN 



ingly interested in the structure of spirillum, and have cultivated 

 those found in horse-dung and in duck-droppings in many ways, 

 yet had never arrived to such a stage as to obtain these demar- 

 cations so clearly. There is a point in these observations that 

 is rather curious, which is the revival, so to speak, of the spirilla 

 after the almost sudden appearance and abundance of the infu- 

 soria, of which only a very feiv were then present, and those of 

 the minutest. Upon further keeping of the material there was 

 no indication of the presence of any of the spirilla, the changes 

 had become so complete as to be inimical to life. 



To make this article a little more complete, it may be as well 

 to state some of the various methods adopted and found most 

 useful in the many examinations. In those cases where the 

 objects in the blood-fluid were not allowed to dry direct on the 

 cover-glass, it was diluted with an equal amount of pure water 

 for after-treatment, and this always on the cover-glass. A very 

 thin ring of Hollis' liquid glue, weakened by wood naphtha, was 

 struck on the slide ; a droplet of water was then put on the clean 

 cover-glass; and then an equal portion of the fluid material, 

 taken from just beneath the surface, was mixed with it, or rather 

 placed on it ; a thin platinum wire, twisted into a loop about the 

 diameter of i/i6th of an inch to the i/r4th (as two sizes were 

 kept at hand), then fixed by melting into the end of a glass 

 rod for a handle, and which I have used for years for the same 

 purpose, enabled me to apportion the amount of fluid on the 

 cover so that it did not run beyond the ringed space. After waiting 

 a short time for the objects to settle more or less on the cover, 

 by means of a pair of weak forceps, it was turned over on to 

 the centre of the ringed spot and allowed to fall gently. It was 

 then examined under the microscope, using the i/5th objective 

 with No. I ocular, and if sufficiently clean and worth the trouble 

 it was further dealt with to fix the objects in position. This 

 was generally effected by placing a small drop of a saturated 

 solution of tannic acid in water at one part of the edge of the 

 cover, at the same time placing the point of a strip of thick 

 blotting-paper at the opposite side. This effected a suction of 

 the tannin under the cover-glass and across the objects ; if the 

 little stream appeared to flow too violently or too much in one 



