PROGRESS OF MICROSCOPICAL SCIENCE. 
203 
sea-coasts, or whore the sea-water during high tide flows into the fresh- 
water ditches, or mouths of rivers, are particularly rich in forms of 
different genera. The tide washes these microscopic bodies loose 
from the ground, and the water collected near the bank contains them 
in great abundance. Filtering large quantities of such water, leaves 
them on the filter, and they can be gathered ; a method of procuring 
them mentioned first by Ehrenberg. I have also practised the follow- 
ing methods : I have taken off the brown skin or slime, with a knife, 
or spatula, pressed the water out, wrapped the remnant in paper, and 
thus carried it off. In the same way I treated the other forms, which 
either as foam, or slime skins, appear swimming on the water. The 
species found on Confervas, or other algae, I gathered with these, 
pressed the alga;, and thus transported them. The separate packages 
I emptied into as many vials, at home, and poured water on the 
masses, then subjected them to the microscope, and afterwards pre- 
served them, either in vials with alcohol, or spread out and dried on 
plates of mica ; in the lack of mica plates, one can use little slips of 
glass for the same purpose of spreading and drying. In this way, all 
the forms found in one region can be preserved for an indefinite time. 
The larger, complex forms of the sea, e. g. Schizonemae, Micro mega;, 
which are found attached to algae, stones, and other objects, may be 
preserved either in alcohol, or dried like the algae, on paper or mica 
plates. In the examination of these, as with all forms, they must first 
bo wetted and softened by water. The dead individuals sink to the 
bottom of the water, and since their siliceous shells resist solution, as 
well as decomposition, they can be found therein even after thousands 
of years. And thus it may happen that these siliceous shells may get 
into the fertile humus, and form a part of it, but their presence therein 
is, generally, purely accidental, and only common in such places as 
are frequently flooded, or have in former times been the bottom of a 
swamp, or standing water, e. g. most peat-layers, in which, in addition 
to the diatom frustules, remnants of different water and swamp plants, 
and also snail and mussel shells are found. No diatom shells are 
found in the soil of dry regions. 
Laticiferous Vessels in Plants. — ‘ Nature,’ of August 9, states, that 
a very interesting Russian paper, by M. Schmahlhausen, has just 
appeared, “Researches on the Vessels of Plants.” The author shows 
that the growth of the vessels goes on in the same manner as that of 
the mycelium of parasitic fungi in the tissue of plants, and thus 
refutes the often expressed opinion that vessels in plants are analogous 
to the blood-vessels in animals. 
Parasitic Infusoria. — Professor Leidy, who recently (June 12) 
read a paper on this subject before the Academy of Sciences of Phila- 
delphia, stated that most of the known parasitic infusoria possessed 
a mouth like those which lived on ordinary water. Such is the case 
with the species of Palantidium found in the intestinal canal of man, 
the hog, and various batrachians ; of Nyctotherus, found in the intes- 
tine of frogs, several insects and myriapods ; and the ConcJiophthirus 
anodontce, often found abundantly on the branchiae and palpi of our 
Anodon fluviatilis. Other parasitic infusoria are not only devoid of an 
