THe Norteern Muicroscopisr 


No. 20. ZO COSE 1882, 


LIFE-HISTORIES AND THEIR LESSONS. 
By Rev. W. H. Datuncer, F.R.S., F.R.M.S. 
(Continued from page 177.) 
Ise a also tells us that Achlya is an aquatic form of 
Sporendonema musce ; that the filaments are devoid of septa, 
and that the tubes contain a colourless granular protoplasm, denser 
on the walls, and that there is an irregular spiral movement in an- 
astomosing currents exhibiting the circulation of the cell contents, 
such as is met with in hairs of Tradescantia. 
In truth, then, what has been presented to us as a remarkable 
transformation of the “protoplasm of a dead fly’s leg” into this 
circulating protoplasm of a Saprolegnia, was neither true as an 
inference nor new as a fact, except to the gentleman who offered 
it as an evidence of the heterogenetic origin of living things. It 
is one of the commonest events of the autumn to see “dead flies 
on the window pane,” and we need not wait even for this phoeno- 
menon to get the Achyla prolifera. The aérial condition of 
the fungus need not precede it. Throw a few flies into water, 
and in a day or two many of them will be covered, in all proba- 
bility, with Achlya. 
In Plate II., Fig. 7, we see the manner of its growth upon the 
decaying leg of an insect. At @ (out of its natural position on the 
thread, for the convenience of illustration) is seen the sexual mode 
of increase, a being the oogonium and @ ¢ the antheridia. The 
method of asexual reproduction is seen in the same Plate, Fig. 
8, where the end of the thallus, 2, becomes densely packed with 
spores ; a septum is formed at the base 4, and ultimately the whole 
centents are poured out from the tip, as at ¢ as minute ovate 
spores, having one or two delicate flagella, as seen in a more 
magnified spore at d, which, like Bacteria or Monads, have the 
power of free movement. Soon, however, they settle on a suitable 
and exciting substance, as the dead body of an insect, or the living 
VoL, 2. 
