llhrioniii'] iXFUsoRiii. axtmalcules. 167 



practicable. In Spirillum the constrictions or ai-ticulations are 

 oblique, so that increase in length by di\'ision engenders a spiral 

 chain . 



The animals of this family "ai'e (says Dujardin,) the first Infusoria 

 wliich present themselves in all infusions, and those which from 

 their extreme smaUness and the imperfection of our means of obser- 

 vation must be considered the most simple ; .... and it is only 

 their more or less active movements which lead to their being 

 regarded as animals. I have been sometimes induced to believe that 

 a flagelliform filament, analagous to that of Monads, or rather a spiral 

 undulating one, exists ; causing the peculiar mode of locomotion. Is 

 the Bacterium ^/77o<;«fore, described by Elu'enberg as having a proboscis 

 a ti'ue Vibrio ? 



AU that can be Avith certainty predicated respecting their organi- 

 zation is that they are contractile, and propagate by spontaneous 

 fission, often imperfect, and hence giving rise to a greater or less 

 increase in length. 



The Vihrionia are developed with extreme rapidity in all liquids 

 containing changed or decomposed organic substances. 



Wagner and Leuckliart, speaking of the sort of motion in cyHn- 

 diical-shaped spermatozoa, make this general remark, " They are 

 principally limited to a bow-shaped curvatiu^e, similar to the motion 

 of the Vihrionia which, like the Ilonadina, belong to the vegetable 

 kingdom, and may undergo a fiu'ther development into fibrous fungi. 

 ( Cyclopcedia Anatomy Art. Semen, p. 503. y 



Dr. Burnett, of JSTew York, has written a paper to prove that the 

 Vihrionia are plants. He says the only assignable reason for con- 

 sidering them animals is their supposed voluntary motion ; a suppo- 

 sition to which he is opposed. As evidence of their plant-nature, 

 he adduces the fact of their branching, like Algae ; an occurrence 

 particularly observable in Sjjirillum. He believes the smaller are 

 only the younger forms of the larger species ; and that they propa- 

 gate by gemmation, and not by fission only, as Ehrenberg states. 



Concerning the so-caUed voluntary motion of the Vihrionia, Dr. 

 Burnett remarks : " It is because the motions have a kind of directive 

 character that they have been called vohintary ; a condition neces- 

 sarily implying a dii'ect act of perception on the part of the form 



