223 
It is identical with the substance which as Plasma or Proto- 
plasm forms the contractile living substance of all organic 
Plastides ; of all cells and Cytodes of animals, Protista, and 
plants. To distinguish it from the encapsuled Protoplasm 
enclosed in cell- or cytode-membranes, the name of sar- 
code, used by Dujardin, can be applied to the free Plasma 
without a covering to protect it from contact with the outer 
world. Only r it must not be forgotten that the naked sarcode 
possesses essentially the same properties as the encysted Pro- 
toplasm, and that in the above-described Protomyxa and 
Myxastrum, for example, and also in the Protomonads 
and Vampyrellte the sarcode must be called protoplasm as 
soon as these Moners encyst themselves, and enclose them- 
selves within an outer membrane ; in other Avoids, as soon 
as the Gymnoplastides pass into Lepoplastides. In the 
indisputable fact that in the aboA'e-mentioned organisms 
the Avhole body (in its perfectly developed state !) actually 
consists singly and only of a jelly-like structureless Proto- 
plasm, and that this simple homogeneous material, as the 
active substratum of all life-movement, ivithout the co-opera- 
tion of different parts, fulfils all essential vital functions 
(nutrition and reproduction, motion and irritability), I see 
sufficient reason to take the step of placing these organisms to- 
gether as Monera in contradistinction to all others, as I have 
done in my ‘ General Morphology.’ For these organisms 
manifestly stand in the loAvest grade below all other organic 
beings, and not only occupy actually the simplest, but also the 
simplest conceiA-able, position of independent living matter. 
But as these remarkable Monera are from one point of vieAV 
of the greatest interest, so from another they deseiwe general 
attention from the inestimable importance Avhich they possess 
of affording a mechanical explanation of vital phenomena, and 
especially for a Monistic explanation of entire organic nature. 
The Protoplasm or Sarcode theory, that is, that the albu- 
minous contents of animal and vegetable cells (or more cor- 
rectly, their “cell-matter”), as Avell as the freely moving 
sarcode of Rhizopoda, Myxomycetae, Protoplasticlae, &c., are 
identical, and that in both cases this albuminous material is 
the original active substratum of all vital phenomena may 
perhaps be considered one of the greatest achievements of 
modern biology, and one of the richest in results. After this 
theory Avas brought foiuvard in its elementary form by Cohn 1 
in 1800, and by Unger 2 in 1853, it Avas further deA'eloped in 
* F. Cohn, “ Nachtrage zur Naturgeschichle des Prolor.occus plnvialis;” 
‘Nova Acta Ac. Leop. Carol.,’ vol. xxii, pars 2, p. C05, 1850. 
* Unger, ‘Anatomie und Physiologic der Pflanzen,’ 1855, pp. 280, 282. 
