DR. BEALE, ON THE MICROSCOPE. 267 
of the same force. The same argument which demonstrates 
the relation between motion and heat will demonstrate the 
relation between heat and vital force; and we are forced to 
believe that, as heat is motion in the red-hot poker and the 
liquid water and gaseous steam, so the same force is exhibiting 
its agency in the growth and changes of the vegetable and 
animal cell. 
We conclude our notice of this admirable volume by an 
extract from that department of the work intended for the 
instruction and guidance of young hands: 
“319. Of Recording Microscopical Observations.—Taking notes of 
microscopical observations is a subject of great importance. The 
observer must endeavour to acquire the habit of describing in words 
the appearance of objects under the microscope. This is probably 
not so easy as would at first be supposed, although undoubtedly 
many persons are able to describe what they see much more correctly, 
and with greater facility, than others. Accuracy in describing 
microscopical specimens can only be acquired by practice, and I 
think it a most excellent rule to take notes of the appearances of 
every object submitted to examination. The time is well spent, and 
much of what is so described is retained in the memory. The notes 
should be short, and should consist of a simple statement of points 
which have been observed. Inferences should be carefully avoided, 
and nothing should be stated without the observer being thoroughly 
satisfied of its accuracy. If he is not quite certain of any observa- 
tion, he should express his doubts, or place a note of interrogation 
after the statement. The use of indefinite terms should be avoided 
as much as possible, and whenever any particular word is used, a 
definite meaning should be attached to it. Much confusion has 
arisen from the use of terms which have not been well defined. Thus, 
the word ‘granule,’ by many authors, is applied to a minute particle 
which appears as a small speck even when examined by the highest 
powers, as well as to a small body with a perfectly clear centre, and 
with a well-defined sharp outline, which would be more correctly 
termed a small ‘ globule. So, again, the term ‘ molecule’ has been 
employed in some cases synonymously with ‘ granule,’ but it would 
obviously be wrong to speak of a small globule as a molecule. It 
seems to me very desirable to restrict the terms ‘granule’ and 
‘molecule’ to minute particles of matter which exhibit no distinct 
structure when examined by the highest powers at our disposal, and 
the term ‘ globule’ to circular or oval bodies of all sizes which have 
a clear centre, with a well-defined dark outline. Other examples of the 
use of insufficiently defined terms might be pointed out. If an 
observer makes use of a term which is generally employed without 
any definite meaning being attached to it, he should describe at 
length the meaning which he assigns to it, and should, of course, use 
it only in this one sense. 
“320. Exactness of Description should always be aimed at, and we 
must remember that with a little trouble this exactness may be 
obtained with the use of a small number of words. That appearance 
of precision which is often attempted by employing long useless 
descriptions cannot be too much condemned. So, also, the practice 
of some, of describing every object in the field of the microscope 
