3. Spherical spores with punctulated surface--0.007 millimeter in
diameter.
4. Very minute, transparent, bluish-greenish colored spores, with thin
covering and finely granulated contents--0.006 millimeter in diameter.
5. Chroococcoid cells with two larger nuclei--0.0031 millimeter in
diameter. Sometimes biciliated minute cells are found; without any doubt
they are zoospores derived from any algoid or fungoid species.
I cannot say whether there exists any genetic connection between these
various sorts of spores. It seems to me that probably numbers 1-4
represent resting states of the hyphomycetes.
No. 5 represents one and two celled states of chroococcus species belong
to Chroococcus minutus.
The crust of the clayish earth is covered with a reddish brown covering
of about half a millimeter in thickness. This covering proves to be
composed, under the microscope, of cellular filaments and various shaped
bodies of various composition. They are made up of cells with densely
and coarsely granulated reddish colored contents--shape, size, and
composition are very variable, as shown in the figures. _The cellular
bodies make up the essential organic part of the clayish substance, and,
without any doubt, if anything of the organic compounds of the substance
is in genetical connection with the disease, these bodies would have
this role_. The structure and coloration of cell contents exhibit the
closest alliance to the characteristics of the division of Chroolepideæ
and of this small division of Chlorophyllaceous Algæ, nearest to
Gongrosira--a genus whose five to six species are inhabitants of fresh
water, mostly attached to various minute aquatic Algæ and mosses. Each
cell of all the plants of this genus produces a large number of mobile
cells--zoospores.
Fig. 9 represents very probably one zoospore developed from these plants
as figured from 10 to 16.
* * * * *