388 TIMOTHY RICHARDS LEWIS. 



under the influence of the chloroform, ligatures were passed around 

 the several viscera so as to isolate them before death had taken 

 place. Finally, a ligature was passed around the vessels at the 

 base of the heart, and the organ severed from the body. 



The specimens thus procured were repeatedly dipped into 

 either melted paraffin or wax, by means of the string attached 

 to them. In this way they became coated something after 

 the manner of the cotton wick of a candle. Preparations 

 thus made were set aside for from twelve to twenty- four hours, 

 according as the average temperature of the atmosphere was over 

 or under 90° F., and it was almost invariably found that organ- 

 isms appeared in them, almost, if not quite, as rapidly as they 

 appeared in the bodies of animals which had been simply set 

 aside under like conditions. In the former case, however, the 

 supposition that they were derived from the alimentary canal 

 after death is not possible ; nor can it well be maintained that 

 they derived their germs from contact with the scalpel, string, 

 &c., seeing that the entire surface was exposed to the influence 

 of melting paraffin or wax. 



The first figure in Plate XVII represents a tracing of a micro- 

 photograph of the bacilli obtained in the manner above described 

 from the blood of a mouse, to all appearances perfectly healthy 

 when killed. A little of the blood was spread in a thin layer on 

 a glass cover and allowed to dry, then a drop of a solution of 

 anilin-blue was added to the slide, so as to stain the micro- 

 phytes, and thus render them more distinctly visible when 

 focussed in the camera. The photographs were obtained by 

 means of a-fV" object glass (immersion), made by Messrs. Powell 

 and Lealand. 



When first seen in the blood the majority of these bacilli are 

 motionless — in some preparations completely so, but in others 

 they can be observed to manifest more or less distinctly marked 

 independent movements. They vary in size — in length chiefly — 

 according as their development into filaments has advanced. 

 The average length of each rod is found to be either 5 fi or 

 10 /z.^ In the latter case a more or less distinctly marked bend 

 will be recognisable indicative of a joint. In more advanced 

 stages of growth, two, three, or more such joints may be detected, 

 especially on the addition of reagents, such a tincture of iodine. 

 In this case the bacilli will measure either 15, 20, 25, or more 

 micro-millimeters. The length of these segments, whether 



' fi =. micro-millimeter ('OOl mm). This mode of stating the measure- 

 ments is adopted in connection with this series of observations for con- 

 venience of comparison with like observations regarding- Bacillus (inthruch. 

 It will be convenient to remember that tiie average size of a human red 

 blood-corpuscle = 8 /*. 



