ON MICROSCOPIC DISCOVERY. 



629 



. Cylindric, the fore-part papillary. 27. EncMis \ 

 . Kind of ventricose cylinder, 



pupa 



proceeding from the apex 



. . 

 , with a small nipple 



V. VIBRIO. An invisible worm, very sim- 

 ple, round, and rather long. 



" The extensive range of this genus, in re- 

 gard to the structure, form, and size of the dif- 

 ferent species, offers great variety to the ob- 

 server. It includes animalcules both mem- 

 braneous and crustaceous : some as slight as a 

 thread, others whose breadth nearly equals 

 their length ; some whose organization is so 

 complete that modern naturalists have entirely 

 excluded them from the phytozoa ; and others, 

 which are with difficulty distinguished from 

 vegetables. To diminish somewhat the incon- 

 gruities, without rendering the arrangement 

 complex, I have separated them into three di- 

 visions. The first is the simplest, and re- 

 quires a magnifying power of from 200 to 500 

 times to examine them ; the second and third 

 vary so much in size that some do not require 

 half that power, and a few even less, being 

 just discernible by the naked eye." 



First Division, Bacillaria. " These mi- 

 nute and inactive animalcules are covered with 

 a hard, shell-like coat, and appear closely al- 

 lied to some of the fresh-water algae, and are 

 not very appropriately classed with the vibrio. 

 Second Division, Phytozoa. " This term 

 was first made use of by Goldfuss, and is con- 

 fined by Ehrenberg to those microscopic crea- 

 tures whose digestive organs are polygastric, 

 or if they possess a simple alimentary canal, 

 it is always accompanied by rotatory organs." 

 Third Division, Entozoa. Includes those 

 animalcules of the vibrio genus which " pos- 

 sess an alimentary canal, but no cilia, nor oc- 

 casion currents when immersed in a mechani- 

 cal solution of coloured particles." 



Plate 35, fig. 68, and Plate 27, fig. 30. 

 Paxillifer Vibrio. " This animalcule, or 

 rather congeries of animalcules, for they are 

 mostly attached together in different forms, 

 when magnified appear like pieces of straw, 

 of a pale yellow colour, with the inside of an 

 orange brown. They are nearly round, and 

 if attentively watched, may be seen occasion- 

 ally to turn upon their longest axis, when a 

 longitudinal line may be observed ; this is 

 probably the hinge or opening of their shell. 

 They vary in length from 1- 1 00th to l-500th 

 of an inch, their diameter is from l-20th to 

 1-1 00th of their length : they require consi- 

 derable magnifying power, arid large angular 

 aperture, to distinguish thei-r structure. I find 

 on reference to my notes, made at different 

 times, that it was not until after I had exa- 

 mined them repeatedly I became satisfied of 

 their animal vitality. They generally reside 

 at the bottom of .ponds, but after rain are met 

 with near the surface, giving the water a green 



tint ; in such cases they are found separate, 

 the agitation of the water having broken the 

 clusters." These animalcules are generally 

 found collected together in different parcels, 

 from seven to forty in number, and ranged in 

 a variety of forms, sometimes in a straight 

 line, then in the concave, as in fig. 30. This 

 creature, usually known as the stick vibrio, 

 seems to have affinity to the hair-like animal 

 described by Baker. 



Plate 27, fig. 44. Vibrio Lunula. r \\Q 

 bow, or moon-shaped, vibrio, having both ends 

 similar. The body resembles much the shape 

 of the moon at the first quarter ; it is of a green 

 colour, and has generally from seven to ten 

 globules disposed lengthwise ; the smaller ones 

 are of a very pale colour, a pale green vacuity 

 may sometimes be seen in the middle : some 

 few varieties may be observed amongst them, 

 which are not easily described ; it will be 

 enough to have given the reader their general 

 and distinguishing characteristics. 



The annexed cut represents a. kind of vibrio 

 found in wheat These animalcules were dis- 

 covered by Needham, and described by him 

 in a work entitled New Microscopical Disco- 

 veries, and afterwards more fully treated upon 

 by Baker. They are not lodged in those 

 blighted grains which are covered externally 

 with a soot-like dust, whose inside is often 

 little more than a black powder ; but abun- 

 dance of ears may be observed in fields of corn, 

 which have grains that appear blackish, as if 

 scorched: these, when opened, are found to 

 contain a soft white substance, that when at- 

 tentively examined looks like a congeries of 

 threads, or fibres, lying as close as possible to 



