FLAGELLATED ORGANISMS IN BLOOD OF HEALTHY RATS. 113 



application of electricity to microscopic preparations, and 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 consecutive hours. The only difference 

 appreciable between a preparation thus dealt with and one not so 

 treated was, that the movements ceased a few hours sooner in the 

 former than in the latter, possibly owing lo the chemical change 

 induced iu the blood itself by the current. 



I have examined the blood of a great number of rats for the 

 purpose of ascertaining what proportion of them contains these 

 organisms in their blood, and find that of those specially ex- 

 amined for this purpose their existence was demonstrated in 29 

 per cent. Sometimes, however, the number detected were very 

 few, not more than one or two in a slide, but in the greater 

 number of cases they were very numerous, every slide containing 

 several hundreds. 



Being anxious to ascertain precisely the species of rats in 

 which these organisms were found, I consulted an accomplished 

 naturalist, Dr. John Anderson, Superintendent of the Indian 

 Museum, and he was so good as to identify the specimens for me 

 from time to time. The result has been that it has been defi- 

 nately ascertained that these organisms may be found in two 

 species, viz. 3Ius decnmanus and Miis rvfescens. 



It would appear that they are not found in mice. I have 

 examined the blood of a large number, but never detected any 

 organisms of the kind ; nor have I seen them in any animals other 

 than rats. 



It is possible that these minute organisms ought to have 

 been described in the part of this paper devoted to the description 

 of microphytes, as they present many features in common 

 with motile organisms undoubtedly of vegetable origin : on 

 the othef hand, taken as a whole they appear to approach more 

 closely to the forms of life usually classified as Protozoa ; such, 

 for example, as several of the species of Dujardin^s genus 

 Cercomonas. It should, however, be noted that many believe 

 that these organisms are zoospores and not animalcules. 



The nearest approach to a description of these ha3matozoa 

 which I can find is in a recent paper by BUtschli,^ in which 

 he refers to a flagellated parasite which he has often observed 

 in the intestinal canal of a free nematode {Trilohus gracilis). 

 He refrains from giving it a name, owing to the uncertainty 

 which exists with regard to organisms of this kind. He 

 generally found them in large numbers, often forming stellate 

 colonies owing to their being attached by their non-flagellated 

 ends. They readily became detached, and then presented a some- 

 ' See page 68 and Plate VI, fig. 5, of the present number of tliis Journal. 



VOL. XIX. NEW SER. H 



