230 The Microscope. 



infused for some weeks in water, an extremely minute bell-shaped 

 polype is found, among a variety of others, as in fig. 4, and re- 

 quires the greatest power of the microscope to discover their form, 

 for their tails must be many thousand times less than the finest 

 hair of the head. As seen in the plate, they are magnified in 

 bulk six thousand four hundred times, whereby we may form 

 some conception of their minuteness; yet small as they are, they 

 live upon animalcules many hundred times less than themselves. 



The small Snail with Spiral Shell. This description 

 of snail may be procured in ponds and ditches: the more transpa- 

 rent the better. They may be kept alive f|pr months in a large 

 glass vessel; and it is common for them to fasten their spawn in 

 little masses against the sides of the glass, where the eggs hatch 

 in about three weeks or a month. The spawn appears like a 

 transparent jelly; but, examined by the microscope, you may 

 discover a number of oval pellucid bodies, having each of them a 

 dark speck: this speck becomes a perfect snail, and, a few days 

 before hatched, may be seen, in a perfect state, turning about in 

 the fluid that encloses it; the heart also may be distinctly seen, 

 the pulsation proceeding under the eye wiih great exactness and 

 regularity, forming a most beautiful spectacle; a number of the 

 bell-sliaped pol3'pe generally attach themselves to the snail. 



The Proteus. None of the many difl^erent animalcules I have 

 yet examined have aflbrded so much pleasure, perplexity and 

 surprise, as the curious insect I am about to describe, which has 

 so wonderful a capability of assuming different shapes, that nobody 

 without actually seeing its changes would believe it to be the same 

 creature; it may be found in water where any kind of vegetable 

 bodies have been infused, and has stood for several weeks: if it 

 is in any glass vessel, a slimy substance will be collected about 

 the sides; some of this being taken off with the point of a knife, 

 and placed on the slip of glass in a drop of water, it will be found, 

 upon looking at it through the microscope, to harbor several kinds 

 of animalcule; the proteus will most likely be seen among them, 

 and is thus described by Mr. Baker: — 'After having been exam- 

 ining some of this matter for sometime, which I found plentifully 

 stocked with various kinds of animalcules, a little creature sud- 

 denly made its appearance among them, whose figure was entirely 

 new to me, moving about with great agility: the body was ellipti- 

 cal, with a slender fine-proportioned neck, similar to a swan's. 

 Fig. 19 is a representation of this extraordinary insect. It moved 

 its head backwards and forwards, seemingly in search of its prey. 

 After viewing it for sometime with a low power, wishing to change 

 it for a greater, which took up sometime, it was lost to view, and 



