THE THRESHOLD OF EVOLUTION. 153 
typical Monera , instead of being ‘ through life ’ nothing more 
than little lumps of the structureless, &c., protoplasm, and ex- 
hibiting ‘no higher degree of development than that observable 
in pure protoplasm, undoubtedly pass through several stages in 
their life-cycle, and that in two at least of these stages, their 
organization is obviously of a complex kind, even when 
scrutinized in the most cursory manner. Thus we find they 
pass through an Amoeboid, or Actinophryan-\\ke stage, a stage 
of encystment, in which the contents of the cyst — itself a highly 
differentiated portion of the structure — undergo a process akin 
to segmentation ; each segment, in the case of Protomyxa, 
emerging from the burst cyst in the shape of a pyriform, caudate, 
zoospore, which moves about actively, but ultimately takes on 
the Amoeboid form ; and in the case of Myxastrum, emerging 
in the shape of oblong siliceous cysts, which on bursting give 
egress to a little mass of protoplasm, which, as in Protomyxa , 
takes on the Amoeboid (Actinophryan) character — a series of 
facts so significant, that I venture to say they prove incontestably 
that whatever may be the precise position in nature of the 
organisms described, they are not inferior in complexity of 
structure to the Rhizopods. 
In short, the error committed throughout Haeckel’ s obser- 
vations consists in the determination to regard the protoplasm 
of the organisms in question as perfectly homogeneous, because 
he considers this character essential to his hypothesis of their 
having been formed by spontaneous generation. The researches 
of Messrs. Dallinger and Drysdale, already referred to, clearly 
demonstrate this error. In the case of the Monera, which are 
giants in comparison with Messrs. Dallinger and Drysdale’s 
| Monads, the presence of granular particles suffices to upset the 
hypothesis based upon the absolute homogeneity of their proto- 
plasm, in spite of Haeckel’s effort to explain away their un- 
deniable presence on the ground that they are ‘ the products of 
a change of substance — assimilated matter, to be eventually 
changed into sarcode.’ For, what are blood-corpuscules, sper- 
matozoa, and every tissue in an animal’s body, but products of 
a change of substance ? 
Did space permit, it would be easy to show that in the 
Amoeba, when immature, the nuclear body not unfrequently 
escapes observation, owing either to its transparency or to the 
presence of the granular particles, as well as food-particles, 
which make their appearance in the sarcode at a very early 
stage in the life-history of these organisms. The nucleus is, 
however, always present when reproductive division (a term I 
now use merely to distinguish it from simple repetitive divi- 
sion) has taken place ; inasmuch as the former process cannot 
occur unless a nucleus is present ; whereas simple division into 
