143 
THE THRESHOLD OF EYOLHTION. 
By Surgeon-Major WALLICH, M.D. 
{Plate IY.] 
I N order to determine, with at least approximate certainty, 
the starting-point from which animal life took its earliest 
step in evolution, it is obviously essential that we should 
entertain accurate ideas as to the nature and characters of 
those humblest types of being that stand at the bottom of the 
series. Fifteen years ago it was the general belief amongst 
biologists that the Rhizopods, as presenting 4 the distinctive 
attributes of animal life in their least specialized shape/ occu- 
pied the position. But, since then, scientific opinion has under- 
gone an important, and, as I venture to think, prejudicial 
change, through the promulgation by Professor Haeckel of the 
hypothesis that there exists a third kingdom in creation, inter- 
mediate between the animal and vegetable kingdoms, the lowest 
group of which, the Monera , comprises 4 not only the simplest, 
but the simplest conceivable organisms ;’ and hence, with a 
view 4 to satisfy the. requirements of the human understanding 
for causality/ we must accept as an 4 unprovable/ but, never- 
theless, absolute fact, that these organisms 4 originated by 
spontaneous generation at the first beginning of life upon the 
I earth.’ 
The chief aim of the following observations is to prove, on 
the basis of Haeckel’s own descriptions and figures, that the 
structures in question have no locus standi as Monera ; and, 
consequently, that we are as far off as ever from being able to 
say with confidence that they form the connecting link between 
the organic and inorganic world ; or that they were 4 the first 
molecules of matter that took upon themselves the responsibility 
of living.’ * 
* This expression was used satirically bv Dr. Dawson, of Eozoon cele- 
brity, in speaking of spontaneous generation. 
