Monthly Microscopical"! 
Juurnal, May 1, 1869. J 
Boyal Microscoineal Society. 
II. — Protojplasm and Living Matter, By Dr. Lionel S. Beale, 
F.E.S., Fellow of the Eoyal College of Physicians ; Physician 
to King's College Hospital ; and lately Professor of Physiology 
and of General and Morbid Anatomy in King's College, London. 
{Bead hefore the Royal Microscopical Society, A^wil 14, 1869.) 
The frequent use of scientific terms, the meaning of which is im- 
perfectly understood, or inaccurately defined by the authors who 
employ them, is a fertile source of embarrassment to the student of 
science, as well as a serious hindrance to the free difi'usion of correct 
scientific information. And it unfortunately happens that in some 
instances the evil is increased as knowledge advances; for the 
meaning of a word necessarily becomes modified as new facts are 
brought to light, and after a time the word represents something 
very difi'erent from the idea it was originally intended to express. 
Moreover, it sometimes happens that the same word is used by 
several different authors in different senses, and at last accuracy is 
only rendered possible by the introduction of entirely new terms, 
having a definite and restricted meaning. 
The term " Protoplasm " may be adduced in illustration of the 
above remarks. This word is now applied to several different kinds 
of matter, — to substances differing from one another in the most 
essential particulars. It seems, therefore, very desirable that its 
meaning should be accurately defined by those who employ it, or 
that it should be superseded by other words. If certain authors 
who have investigated the subject were asked to define exactly the 
characters of the matter which they called protoplasm, we should 
have from those authors definitions applying to things essentially 
different from one another. Hard and soft, solid and liquid, 
coloured and colourless, opaque and transparent, granular and 
destitute of granules, structureless and having structure, moving 
and incapable of movement, active and passive, contractile and non- 
contractile, growing and incapable of growth, changing and inca- 
pable of change, animate and inanimate, alive and dead, — are some 
of the opposite qualities possessed by different kinds of matter 
which have nevertheless been called protoplasm. 
In this communication I propose to refer very briefly to the 
conclusions which have been arrived at with reference' to the nature 
of the so-called protoplasm, and I shall endeavour to trace the 
gradual changes and alterations which advancing knowledge and 
new theories have occasioned in the meaning of the term. I shall 
ask the Society to consider if it is not desirable that the meaning of 
this word, now in common use, should be more accurately defined 
than it has been hitherto. We may also venture to inquire if some 
