63 S On Flagellated Organisms in the Blood of Animals. [part hi. 



For some time I was inclined to think that they might be the spermatozoa of 

 some parasite hidden in the tissues of the animal, a view which strongly forced itself 

 upon me some years ago, in 1878, by having accidentally observed a large number 

 of spermatozoids escaping from the reproductive pore of a fragment of taenia which I 

 had found while dissecting a rat. The " head " of the taenia was not found, so that 

 the entozoon could not be identified with certainty, but it probably was a portion of 

 Taenia microstoma or some closely allied species. My notes run as follows: — 

 " The segments having been placed on a slide spermatozoids are seen to escape from 

 the genital pore of nearly every one of them. For a few moments after their escape 

 they presented, with amazing exactness, the characters of the spirillar organisms found 

 in the blood of rats, but which were not present in the blood of this particular specimen. 

 It seemed, however, that the water in which the taenia segments were mounted and 

 into which they escaped was not suitable to their preservation. They rapidly underwent 

 changes of form, and almost before half a dozen of them could be sketched disintegrative 

 changes set in, and the previously active flagellated organisms were transformed into 

 quiescent, filamentous shreds." It has not been considered necessary to reproduce the 

 sketches of them which were made, seeing that both as to size and form they are so 

 very like several of the figures in the woodcuts already given. The organisms found 

 in the blood of rats, however, are by no means so sensitive to the action of water as this. 



Leuckart, in his recently published review of the additions which have been made 

 during 1876 to 1879 to the literature of low forms of animal life,* suggests that it is 

 doubtful whether these rat organisms should not be relegated to the class of organisms 

 described by Dr. Graule as being present in the blood and spleen of frogs and termed 

 by him " Cytozoa " rather than to the " Flagellata." Headers will recollect that Dr. Gaule 

 was under the impression that these " Cytozoa " (also described by him as " Wiirmchen ") 

 were the result of certain changes which took place in the blood-corpuscles and other 

 cellular elements of frogs. Professor Ray Lankester, however, in the number of the 

 Quart&rly Journal of Microscopical Science for January, 1882, has shown that such an 

 inference is wholly erroneous, and has, I think, very satisfactorily demonstrated that 

 Gaule's Cytozoa are " independent parasitic organisms " — that they represent, in fact, the 

 young stage of a Sporozoon. It is not quite clear to which view of the nature of 

 these " Cytozoa," to Gaule's or to Lankester's, Leuckart refers in the paragraph above 

 cited. 



In his recently completed "Manual of the Infusoria," Mr. Saville Kent, on the 

 other hand, has placed the blood-organism of the rat amongst the Flagellata, and 

 has named them Herpetomonas Lewisi ; at the same time he points out that 

 it is possible that further research " may possibly demonstrate their identity with 

 the discharged spermatic elements of the minute nematodes, micro-filariae, or other 

 metazoic endo- parasitic forms known to flourish amid the same surroundings." 



* "Bericht iiber die wissenschaftlichen Leistungen in der Naturgeschichte der niederen Thiere," II Halfte 

 1883, p. 775. 



