When Vaucheria has reached the proper stage in its life cycle, slight swellings appear here and there on the sides of the filament.  Each of these slowly develops into a shape resembling a strongly curved horn.  This becomes the organ termed the antheridium, from its analogy in function to the anther of flowering plants.  While this is in process of growth, peculiar oval capsules or sporangia (usually 2 to 5 in number) are formed in close proximity to the antheridium.  In some species both these organs are sessile on the main filament, in others they appear on a short pedicel (Figs. 3 and 4).  The upper part of the antheridium becomes separated from the parent stem by a septum, and its contents are converted into ciliated motile antherozoids.  The adjacent sporangia also become cut off by septa, and the investing membrane, when mature, opens:  it a beak-like prolongation, thus permitting the inclosed densely congregated green granules to be penetrated by the antherozoids which swarm from the antheridium at the same time.  After being thus fertilized the contents of the sporangium acquire a peculiar oily appearance, of a beautiful emerald color, an exceedingly tough but transparent envelope is secreted, and thus is constituted the fully developed oospore, the beginner of a new generation of the plant.  After the production of this oospore the parent filament gradually loses its vitality and slowly decays.

The spore being thus liberated, sinks to the bottom.  Its brilliant hue has faded and changed to a reddish brown, but after a rest of about three months (according to Pringsheim, who seems to be the only one who has ever followed the process of oospore formation entirely through), the spore suddenly assumes its original vivid hue and germinates into a young Vaucheria.

CHARM OF MICROSCOPICAL STUDY.

This concludes the account of my very imperfect attempt to trace the life history of a lowly plant.  Its study has been to me a source of ever increasing pleasure, and has again demonstrated how our favorite instrument reveals phenomena of most absorbing interest in directions where the unaided eye finds but little promise.  In walking along the banks of the little stream, where, half concealed by more pretentious plants, our humble Vaucheria grows, the average passer by, if he notices it at all, sees but a tangled tuft of dark green “scum.”  Yet, when this is examined under the magic tube, a crystal cylinder, closely set with sparkling emeralds, is revealed.  And although so transparent, so apparently simple in structure that it does not seem possible for even the finest details to escape our search, yet almost as we watch it mystic changes appear.  We see the bright green granules, impelled by an unseen force, separate and rearrange themselves in new formations.  Strange outgrowths from the parent filament appear.  The strange power we call “life,” doubly mysterious when manifested in an organism so simple as this, so open to our search, seems to challenge us to discover its secret, and, armed with our glittering lenses and our flashing stands of exquisite workmanship, we search intently, but in vain.  And yet not in vain, for we are more than recompensed by the wondrous revelations beheld and the unalloyed pleasures enjoyed, through the study of even the unpretentious Vaucheria.