FLAGELLATED ORGANISMS IN THE BLOOD OF ANIMALS. 369 



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. Gaule as being present in the blood 

 and spleen of frogs and termed by him " Cytozoa ^' rather than 

 to the flagellata. Readers of this Journal 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 this Journal for January, 1882, has shown 

 that such an inference is wholly erroneous, and has, I think, 

 very satisfactorily demonstrated that Gaule's Cytozoa are " inde- 

 pendent 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 Herpe- 

 tomonas 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-filarise, or other metazoic endo-parasitic forms 

 known to flourish amid the same surroundings." 



1 ' Bericht iiber die wissenschaftlichen Leistungen iu der Naturgeschichte 

 der uiederen Tliiere,' ii Hiilfte, 1SS3, p. 775. 



