278 
Transactions ofJhe 
t Monthly Microscopical 
Journal, May 1, 1869. 
other term might not be more advantageously employed in speaking 
of certain of the substances which have been included under " pro- 
toplasm." Lastly, I shall endeavour to show that in all living 
beings there exists matter in two very different states — living and 
non-living ; and that matter passes from one state into the other 
condition suddenly, not gradually, — that, in short, it is either living 
or not living, and that the living and the non-living cannot be 
regarded as the same substance, and ought not to be called by the 
same name. It seems obvious that if living matter is to be called 
protoplasm, the term should be restricted to this alone, and in no 
case made to include non-living matter, unless indeed it can be 
proved scientifically that there is no difference between living and 
dead, that our ordinary notions on the subject are quite erroneous, 
and that the words " living " and " dead " only serve to mark dis- 
tinctions which are not real, but exist only in our imaginations. 
A definition of protoplasm, most probably written by the late 
Professor Henfrey in ' Griffith and Henfrey's Micrographic Dic- 
tionary,' is as follows : ~" Protoplasm. — The name applied by Mohl 
to the colourless or yellowish, smooth or granular viscid substance, 
of nitrogenous constitution, which constitutes the formative sub- 
stance in the contents of vegetable cells, in the condition of gela- 
tinous strata, reticulated threads and nuclear aggregations, &c. It 
is the same substance as that formerly termed by the Grermans 
'schleim,' which was usually translated in English works by 
' mucus,' or ' mucilage.' " The surface of this mass constituted the 
" formative protoplasmic layer " which was supposed to take part in 
the formation of the cellulose waU of the vegetable cell. This was 
regarded by Von Mohl as a structure of special importance distinct 
from the cell contents, and it was named by him in 1844 the 
" primordial utricle." 
In cases where protoplasm appears as a simple transparent 
homogeneous substance, several layers have been described, and it 
has been supposed that these different layers are concerned in dif- 
erent operations. This view has been extended to many forms of 
protoplasm, and the movements which occur have been attributed 
to the presence of two or more layers differing in density. 
Clear, homogeneous protoplasm, it has been said, undergoes 
vacuolation, and becomes honeycombed, the spaces being filled with 
watery matter. In some instances, this change proceeds until mere 
protoplasmic threads are seen stretched across the cavity. The 
transparent fluid material occupying the spaces and the intervals 
between the threads is supposed to be the less important matter, and 
yet it is the Hving, growing, and moving substance ; while the threads 
and walls of the spaces are composed of matter which has ceased to 
manifest these properties — matter which no longer lives, and which 
has been formed from the living matter. But we may fairly ask if 
