190 NOTES AND MEMORANDA. 



opinion it was necessary to make "serious reserves as to tlie conclu- 

 sions of the author." 



Flagellated Organisms in Rats' Blood. — In the 'Fourteenth 

 Annual Report of the Sanitary Commissioner with the Government 

 of India ' is a paper on " the Microscojiic Organisms found in the 

 Blood of Man and Animals," by Mr. T. E. Lewis, M.B., in which 

 he disputes the correctness of what he terms one of the fundamental 

 tenets of M. Pasteur's creed, viz. that neither microscopic organisms 

 nor their germs are ever found in the blood of an animal in 

 health. 



In July, 1877, he detected organisms in the blood of a rat which 

 he was examining. Under the Microscope, the blood appeared to 

 quiver with life, and on diluting it with a half per cent, solution of 

 salt, motile filaments could be seen rushing through the serum, and 

 tossing the blood-corpuscles about in all directions. Their move- 

 ments were of a more undulatory character than spirilla, and the fila- 

 ments were thicker, more of a vibrionic aspect. They were pale 

 translucent beings, without any trace of visible structure or granu- 

 larity. It was observed that every now and then blood-corpuscles 

 some considerable distance from any visible motile filament would 

 suddenly quiver. On carefully arranging the light, it was seen that 

 this was due to a very long and exceedingly fine (apparently posterior) 

 flagellum. These haematozoa may sometimes be kept alive for two or 

 three days, but generally die and disappear from view within twelve 

 or twenty-four liours, as though they had been dissolved in the serum 

 in which they were found. They may be preserved by spreading out 

 a thin layer of the blood containing them over a thin covering glass, 

 and inverting it over a weak solution of osmic acid. The preparation 

 should be removed as soon as it presents a dry, glazed appearance, 

 and may be thus mounted in the dried condition, or in a saturated 

 solution of acetate of potash. The flagellrmi cannot be detected in 

 such a preparation ; apparently the refractive index of the substance 

 forming the flagellum and that of the serum approximates so closely, 

 that it can only be detected when creating a current by its movements. 



The body-portion may be measured after they have been killed by 

 means of osmic acid. The width of the anterior half or body-portion 

 averages • 8 to 1 /x, or precisely that of ordinary blood-bacilli, and its 

 length from 20 to 30 fx. The flagellum, so much of it as is visible, 

 is somewhat of the same length, though possibly considerably longer, 

 as the slope from the body-portion is very gradual ; and when the eye 

 follows it to the bounds of visibility, an impression is conveyed that 

 there may be still more of it. 



On applying electricity to a drop of the blood, it was found that 

 an interrupted current of such a strength as could not be comfortably 

 borne by an individual was tolerated by these beings for several con- 

 secutive hours. 



The species of rats in which these organisms were found were 

 BIus decumanus and 31. riifescens. They were never found in mice.* 



* 'Quart. Journ. Mic. Sci.,' N. P., vol. xix. (1879) p. 109. 



