MICROSCOPE. 



pellicle or film will be discerned on the surface, 

 which, under the microscope, will be seen to be 

 inhabited by several descriptions of animalcules : 

 the first produce are commonly those of the sim- 

 plest kind called Monads. In a few days more, 

 their numbers will increase to such an amazing 

 extent, that it would be utterly impossible to com- 

 pute those in a single drop of the fluid. After 

 this, again, they will begin to diminish in numbers, 

 and I have generally observed them supplanted by 

 others of a larger species and more perfect organiza- 

 tion ; such as the Cyclidia, Paramesia, Kolpodce, 

 &c. It is worthy of remark here, however, that 

 in their production they do not pursue any regular 

 order, even in similar infusions. If the vessel be 

 large, and the circumstances under which it is 

 placed sufficiently favourable, a still higher de- 

 scription of animalcules will succeed, viz., the 

 Vorticella, and, lastly, the Brachione ; and thus a 

 single infusion will repay for the little trouble of 

 making it with a great variety of species. Water 

 in which flour has been steeped will be found to 

 abound also with animalcules : and it is remarked 

 by G. Leach, Esq., that the leaden troughs, con- 

 stantly appropriated for birds to drink out of, con- 

 tain several descriptions of them, and more espe- 

 cially those of the wheel genus. In ponds, too, 

 especially in the shallow parts, near their edges, 

 and in the immediate vicinity of water plants, pro- 

 digious quantities of all kinds may be easily pro- 

 cured ; so that possessing as we do such myriads of 

 them all around us, that they impregnate almost 

 every thing that we eat, drink, touch, and breathe, 

 an anxiety to know more about them, and the 

 effects they produce, cannot but be regarded as ra- 

 tional and laudable." 



" By a careful inspection of the Drawings," (Mr 

 Pritchard refers to the elaborate engravings illus- 

 trating his Natural History of Animalcules,) " it 

 will be noticed that some animalcules resemble 

 spheres, others are egg-shaped ; others again repre- 

 sent fruits of various kinds; eels, serpents, and 

 many of the invertebrated animals ; funnels, tops, 

 cylinders, pitchers, wheels, flasks, &c. &c. ; all of 

 which are found to possess their own particular 

 habits, and to pursue a course of life best adapted 

 to their peculiar constructions : thus, for instance, 

 while some move through the water with the 

 greatest imaginable rapidity, darting, leaping, or 

 swimming, others merely creep or glide along; and 

 many are altogether so passive that it requires long 

 and patient observation to discover any of their 

 movements at all. One description are percepti- 

 bly soft, and yield easily to the touch ; another are 

 covered with a delicate shell or horn-like coat. 

 Of the latter order there are different degrees of 

 density, as in the Volvox, Gonium, &c., where the 

 envelope is comparatively thick; and where, 

 strange to say, the internal substance separates by 

 the mode of propagation into several portions, 

 forming so many distinct young ones, which at 

 their birth burst the envelope and the parent 

 becomes entirely dissipated. In others of this 

 order the shell is merely a plate covering the body, 

 resembling that of the tortoise : sometimes it in- 

 cludes the body, so as to leave only two small 

 apertures at the extremities, and at others it is 

 bivalve, and incloses the creature, like that of tMj 

 oyster or muscle." 



" All vertebrated animals are either oviparous 

 or viviparous, which terms sufficiently designate 

 their modes of production : but it is not so with 



animalcules ; for, in addition to these two methods 

 1. Animalcules propagate by a spontaneous 

 scissure, or division of their bodies into two or 

 more portions, each one forming a new creature, 

 which, on its arrival at maturity, pursues the same 

 course. These divisions take place in some genera 

 symmetrically, as in the Gonia, &c. ; in others by 

 transverse, longitudinal, or diagonal sections. In 

 these latter cases the produce have forms differ- 

 ently proportioned from those of the creatures 

 from which they spring. 2. They propagate, in 

 the manner before mentioned of the Volvox, and 

 some other genera, by a distribution of the internal 

 substance of the parent into a proportionate num- 

 ber of young ones, all of which at their birth issue 

 forth, and leave behind them nothing but the in- 

 velope, soon to be dissolved. 3. They are pro- 

 duced by germs, shooting forth from the parents' 

 sides. 4. From spawn, which, in the act of being 

 shed, carries along with it a portion of the parent 

 animalcule." Pritchard 's Natural History of Ani- 

 malcules, book I. p. 12 20. 



In the foregoing extract we have given Mr 

 Pritchard's lucid and perspicuous summary of all 

 the peculiarities connected with infusorial anima'- 

 cules; and we have studiously avoided any verbal 

 alterations or omissions beyond what were abso- 

 lutely necessary to its present isolated position. 

 We feel that we 'have pushed our license to the 

 extreme by quoting so largely ; but we could no.f 

 by a shorter excerpt have conveyed the informa- 

 tion we desired, and indeed, had we attempted to 

 do so, we should probably have presented the 

 author's statements in a mutilated and garbled 

 form, discreditable to ourselves and injurious to 

 the character of his work. As we are farther in- 

 debted to Mr Pritchard for permission to copy a 

 variety of figures from his book, we must neces- 

 sarily refer to it again in the course of describing 

 our illustrations. We trust, however, that we 

 shall not be found to have misused the liberty 

 conferred ; and that all our excerpts, much as they 

 must add to the value of the present essay, will 

 only serve to convince the naturalist and curious 

 inquirer, that his book is a necessary addition to 

 their libraries, both with regard to copiousness of 

 information, and the extreme truth and beauty of 

 the illustrative engravings. 



It would lead us too far away from the legiti- 

 mate design of the present article to detail a va- 

 riety of additional and interesting particulars rela- 

 tive to the Infusoria, that are recorded by Ehren- 

 berg; it may, however, be proper to make brief 

 allusion to them. He has clearly demonstrated 

 that the Infusoria are furnished with mouths and 

 teeth, and he has even ascertained the number of 

 the latter, their consistency, and characteristic 

 differences. He has found them to be provided 

 with assistant organs of digestion, respiratory 

 organs, and a perfect vascular and nervous system. 

 Even the eyes of these minute objects have been 

 made the subject of his examination, and many re- 

 maikable particulars concerning them have been 

 ascertained. Regarding their fecundity it is suffi- 

 cient to state, on the professor's authority, that a 

 single animalcule will in the course of three or 

 four days become a multitude of separate existences, 

 of whose number the human mind can form no 

 idea. The inquiries of the same unwearied ob- 

 server, relative to fossil infusoria, have issued in 

 such amazing results, that we dare not in our nar- 

 row limits even trace their outline. Let it suffice 



