196 THE AMERICAN MONTHLY . [October, 
and more limiting the term ‘ protoplasm,’ and applying the term ‘ true pro- 
toplasm’ to the chemical substance of highest elaboration, which is the im- 
portant living part of Von Mohl’s protoplasm. Prof. Lankester suggested 
that the term ‘ plasmogen’ should be used for this chemical substance, so as 
to avoid misunderstanding. With regard to the structure of protoplasm, he 
held that it was vesicular, the reticulum or walls of the vesicles being the part 
of the protoplasm in which the plasmogen resides, which is not contained in 
vesicular spaces. The plasmogen was probably most abundant in the nucleus, 
and the idioplasm and germ-plasm of Prof. Weissman were varieties of the 
plasmogen. Prof. Marshall Ward agreed with Prof. Lankester as to the ne- 
cessity of a new word. ‘They ought to seek for names for those parts into 
which they were breaking up protoplasm anatomically. They must remem- 
ber that it was a step forward in itself to have brought before them clearly 
defined ideas as to the substances or structures contained in protoplasm.— 
Eng. Mech.,. Sep. 2, ’847. 
EDITORIAL. 
The address of Professor Rogers, of Colby University, at the recent 
annual meeting of the American Society of Microscopists, is an interesting 
article upon the microscope as an instrument of exact physical research. 
The prelude to his paper upon microscopy as a science contains many very 
sensible remarks, calling attention to the fact that the microscope has found 
its application as an instrument of exact research in very many directions. 
‘ The limitations which necessarily belong to a definition of physical science 
are clearly expressed by Tate in his most admirable treatise on heat. He 
says :—‘‘ Nothing can be learned as'to the physical world save by observation 
and experiment, or é6y mathematical deductions from data so obtained.” 
Now the microscope as an instrument of research stands unrivalled, not only 
in respect to the precision of the observations made with its aid, but also in 
the universality of its application in furnishing what Tate calls ‘‘the data so 
obtained.” 
‘Each succeeding year witnesses an extension of the range of its applica- 
tions. Within a few years, while retaining its claim as an essential factor in 
scientific research, it has also become a very material aid in many mechanical 
industries. It is a common impression that the microscope is too delicate an 
‘instrument to be used in the ordinary operations of mechanical construction, 
and that the apparent necessity of using transmitted light for the purpose of 
illumination is an absolute barrier to any extended employment of the instru- 
ment. The latter difficulty is entirely obviated by the use of the opaque illu- 
minator invented by Tolles, by which a bright metal surface can be examined 
with the utmost ease, while actual experience has shown that it is by no means 
necessary that the instrument should be mounted upon massive piers insulated 
from surrounding objects.’ 
O 
This defense of the claim of microscopy to the title of a science does 
not seem to us to be especially valuable, because there seems to be no dispute_ 
as to the facts and claims in the case except as to a matter of nomenclature. 
Microscopy as a science means, according to Prof. Rogers, that there has 
been a vast accumulation of knowledge regarding physical nature, made by 
the use of the microscope, which he would call the ‘ science of microscopy.’ 
Part of this we are prepared to fully corroborate, and are heartily inter- 
ested in noting every new application of the instrument and every improve- 
