ANIMAL MICRO-PARASITES. 



H.EMATOZOA OF RATS. 



Iii describing these organisms, Lewis remark.-! (hat it wa 

 strange that they had not occupied attention before, and suggested 

 as an explanation that possibly European rats did net hai-Uur these 

 parasites. The author examined a few white rats, but \\iihout 

 success, and then proceeded to examine the blood ..f (-nun..,, 

 rats, trapped from the London sewers, and discovered that these 

 organisms are to be found in no less than 25 per cent, of apparently 

 healthy animals. The first question which naturally arose wa 

 whether these organisms in European rats were identical with those 

 described by Lewis in Indian r.r 



If we refer to the description given 1>\ L \\i>. \\e lind that he 

 states that when he first noticed them he thought they were vibrios 

 or spirilla. The drop of blood 

 under examination appeared to 

 quiver with life ; and on diluting 

 the blood, motile filaments could 

 be seen rushing through the 

 serum and tossing the blood- 

 corpuscles about in all directions. 



The filaments were pale and 

 translucent, without any trace 

 of visible structure or granu- 

 larity, and they were more un- 

 dulatory in movement than , Bux)n 



spirilla. A corpuscle might be OF RATS (Lewis). 



observed to quiver, and thi> 



could be distinctly traced to be due to the existence of a flagell.m., 

 apparently a posterior flageUum, as the organisms seemed generally 

 to move with the thicker end forward; no flap-Hum ..iM 

 detected at the opposite end. The greater numb i 

 in the woodcut (Fig. 239) are dex-ril-d as representing these 

 organisms a few hours after the blood had been obtained, when 

 their movements are not so rapid, and the flagellum becomes more 

 ea>ily recognisable. 



This observation led Kent, who named the organism Uer t 

 Lewiri, to remark that if, as L-wi> H inclined to 

 organ "propels instead of draws the animalcule . 

 habited serum, we have presented a struct ,,,-,,1 tnd t 

 without parallel among the other represents 

 flaffeUata, the recognition of which would demand .- 



