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PROGRESS OF MICROSCOPICAL SCIENCE. 
duction. In proof of this he gives a number of figures — copies of 
Mr. Dallinger’s plates in this Journal — and cites the following quota- 
tion from one of the many papers which the Eev. Mr. Dallinger and 
Dr. Drysdale have communicated to our columns : — “ Two of the 
monads, in no way distinguishable from one another, at times met 
and touched at their anterior ends, swimming freely together. The 
normal flagella rapidly disappeared, and the bodies melted into each 
other, and the whole assumed a granular condition.” Subsequently, 
Mr. Michels remarks : — “ Now, sir, there appears to me to be so close 
an analogy between the blending of the bodies of the Amoebae, as seen 
by Dr. Leidy, and the melting into each other of the monads observed 
by Messrs. Dallinger and Drysdale, that I cannot resist the conclusion 
that they had reference to one and the same act. I beg to make this 
as a mere suggestion, with no desire to disparage Dr. Leidy’s inter- 
esting observations, but rather to offer a rational solution to what he 
himself considered an abnormal act.” It occurs to us that Mr. Michels 
is probably right with regard to his explanation. 
Where Diatoms may be found. — The following observations from 
Professor Smith’s translation of Kutzing’s work in the ‘American 
Journal of Microscopy’ (July), may not be uninteresting to our 
readers. He says that diatoms are found in almost all waters, or in 
wet or damp places. But those who suppose that these organisms 
occur in every drop of water are mistaken. In pure river or spring 
water they are rarely found, but near the banks of the rivers, and in 
the places where springs flow out, in water tables, and in damp places, 
around water pumps, and on the stones and plants which are under the 
water. The fine-threaded marine and fresh-water algas are often very 
richly covered with them— sometimes so completely that the alga) 
cannot be recognized. Frequently, also, in summer, they are to be 
found in the little pools of drying ditches, or in the rain-pools, where, 
on the slippery ground, they form a more or less slimy skin, generally 
tender, but sometimes compact, and which is frequently characterized 
by a brown colour. On warm, sunny summer days, bubbles of oxygen 
are developed in these masses, buoying them up, and bringing them 
to the surface, where they then appear floating either as a thin and 
tender brown skin, or as larger, thicker, very slimy and compact, 
skinny or lumpy masses, from which a notable quantity of oxygen gas 
can be collected. The microscope shows that in these fine skins, very 
different forms arc associated, usually Navicula), Cymbellas, Surirellre 
or free Synedrie, with a more or less lively motion. The larger slimy 
masses consist principally of one species, and if others are found 
among them, they must be considered as accidental mixtures. The 
thread-like forms of Melosira stick to plants, stones, woed, &c., in 
standing or flowing ditches, forming tender, brownish, thread-like 
masses. Others, e. g. Fragilariae, are usually found on rotting tree or 
other leaves. Also among Conferva), mixed with Cymbellas, Synedrie, 
and other forms. It seldom happens that one species is found quite 
isolated from others. The adherent forms are generally found on the 
fine-threaded marine or fresh-water alga), the former yielding the 
complex larger attached forms; the latter, especially, the small, 
isolated, free movable forms. The brackish waters in the vicinity of 
