


No. 19. HOLY, 1882. 


LIFE-HISTORIES AND THEIR LESSONS. 
By Rey, W. H, Datuncrr, F.R.S., F.R.M.S. . 
i paper is extremely simple in its aim, It was written (with 
no intention to publish) at the request and in the interests of a 
large number of microscopists and amateur students of the phe- 
nomena of life as seen in the flora and fauna of our ponds, ditches, 
and sea-side, as well as in septic fluids. Some industrious observers 
amongst them had, from a desultory method of observation, of 
necessity, met with paradoxical phenomena. The products of 
pond and ditch were placed for an indefinite time in “live boxes,” 
kept as long as possible from evaporation. The results were the - 
inevitable commingling of life and death; the destruction or 
decomposition of one set of forms providing nidus and pabulum 
for quite another. In all probability the life-histories of none were 
teally known, and parasite, epiphyte and septic organisms succeeded, 
or were concurrent with, each other. ‘The possibility of erroneous 
interpretation in such a case is immense, specially when the 
“observation” is broken and occasional. The result has been, 
that ardent minds have endeavoured to show that some of the 
Issues observed were only to be accounted for on the hypothesis 
of “ Heterogenesis.” 
Some of the cases appeared striking; and at the instance of a 
large number, who thought good service might be rendered by it, 
I have taken a series of similar or corresponding instances to 
interpret the anomalies, and show that ‘“ Heterogenesis” is no part 
of the phenomena of minute life when studied with sufficient care 
and continuity. It is in deference alone to the strongly-urged 
Tequest of these that the discourse is printed. 
We have frequently, during the past few years, had our attention 
called to apparent anomalies in minute organic forms and minute 
organic processes. In these, besides the portraiture of what were 
considered the “facts,” there has been an attempt made to show 
Von 2: 
