Aside from what may be called the practical value of the study, in- 
cluding that which leads to the better understanding of the higher forms of 
living things, these microscopic creations have many attractions for the stu- 
dent. Nature is always, and to every one, interesting ; her pursuit is alluring 
in the highest degree. To see rare forms men traverse oceans and make pil- 
grimages over continents ; but here are countless unseen living things, 
under our feet, on every side, in the air we breathe, in the food we eat, on 
plants, on animals, germinating and propagating under our own finger nails 
and even in our mouths, possessing a variety of form and structure, often 
curious and beautiful, never equalled by art and not surpassed in nature. 
Their wonderful life-histories stimulate inquiry, engage and enchain the 
attention. He who possesses a microscope, with the ability and opportunity 
to use it, need never wander from his own door to find an abundance of 
material awaiting his researches, and entertaining and instructive biogra- 
phies ready for his pursuit. (10.) 
The Peronosporee. (11). Among the pests to the cultivators of fields 
and gardens, the members of this family maintain a bad pre-eminence. 
None have attracted more attention from the injuries they do to important 
plants, and from their peculiar and interesting life-history. Formerly 
classed in widely different groups on account of their difference in structure, 
ihe species have been united from their agreement in development. All 
produce conidia , — naked spores borne upon the tips of erect filaments or 
kyphae, — which in some cases germinate directly and sometimes give origin 
to some half-dozen zoospores. The latter are small, more or less globular 
bodies, capable of rapid movements in water by means of two long cilia, 
which they lash from side to side with astonishing rapidity. They thus 
swim in a drop of rain or dew some minutes or hours ; then, losing the pro- 
pelling hairs, settle down, and under favorable circumstances germinate like 
the conidia by protruding one or more slender tubes, which penetrate the 
tissues of the supporting plant and become the mycelium or vegetative 
threads of the fungus. Besides, through the conidia and their offspring, 
the zoospores, these particular plants have another method of reproduction. 
The term oospore has been given to a fruit-body found to arise from the 
conjoined action of two separate ceils of the mycelium. This is a sexual 
process well known among the algae or sea-weeds, but not yet well made out 
in most fungi, and analogous to the production of seed in flowering plants 
by the united action of stamen and pistil. The cell producing the oospore 
is called a gonosphere or oogonium , and its partner an antheridium. The 
oospores are found on or in the tissues of the host, sometimes only upon 
one of several plants that the conidia are found upon. Unlike the latter, 
they lie dormant for some months, but, like them, finally give origin to 
10. Cooke’s little book on Rust, Smut, Mildew and Mould is an excellent one 
for a beginner. 
11. The plants enumerated in this paper are from collections made by the 
author between September 21st and and October 16th, 1876, mostly from the area 
of ground upon which he makes his home. Any collector will perceive that more 
of the Uredmes and other families are omitted than are mentioned. 
