456 
in the study of the development of the lower animals. Since it 
has become clear that a knowledge of the precise relations of 
living things one to another can only be arrived at by watching 
the changes through which they pass in the course of their deve- 
lopment, research has been vigorously turned in this direction, 
and although an immense mass of facts has long since been 
accumulated regarding this question, Parker’s brilliant researches 
on the development of the skull give an indication of the great 
things we may yet anticipate from this kind of research. 
Speaking of microscopical study before this audience, I cannot but 
remember that in this country more than in any other we have a 
number of learned gentlemen who, as amateurs eagerly pursue 
investigations in this department. I confess that I am always 
sorry to witness the enthusiastic perseverance with which they 
apply themselves to the prolonged study of markings upon 
diatoms, seeing that they might direct their efforts to subjects 
which would repay them for their labours far more gratefully. I 
would venture to suggest to such workers that it is now more 
than ever necessary to abandon all aims at haphazard discoveries, 
and to approach microscopy by the only legitimate method, of 
undergoing a thorough preliminary training in the various 
methods of microscopical investigation by competent teachers, of 
whom there are now plenty throughout the country. 
State of Physiology 
With regard to physiology, the present standpoint is not so 
high as in the case of anatomy. Physiology, resting as it does 
upon a tripod consisting of anatomy, physics or mechanics, and 
chemistry, is many-sided, The most minute anatomy, the most 
recondite physics, and the most complex chemistry, have all to 
be taken into account in the study of the physiology of living 
things ; so that it is not surprising that it should, in its develop- 
ment, lag behind the comparatively elementary subject—anatomy. 
Until not so very long ago anatomy and physiology were in most 
of our medical schools taught by the same professor, who, 
although professing to teach both subjects, was generally more 
an anatomist than a physiologist. This arrangement gaye to 
physiology a bias which was eminently anatomical, and this bias 
continued in many quarters, notwithstanding the separation of 
the physiological from the anatomical tuition. Iam aware that 
there are still some distinguished anatomists who intermingle 
physiological with anatomical teaching. 
the usefulness of the practice when carried to a moderate extent. 
I wish merely to point out what appears to me to have been a 
result of the practice, and I believe that the result was to give to 
physiology an anatomical tendency. It was natural for the ana- 
tomist who dealt with visible structure to constantly refer to this 
in explaining physiological action or function. The physiologist 
with the anatomical tendency always tried to explain a difference 
in the action or function of a part by a difference in its evident 
structure, and when his microscope failed to show any structural 
difference between the cells which form saliva and those which 
produce pancreatic fluid, between the egg of a rabbit and that of 
a dog, he, baffled on the side of anatomy, was too ready to adopt 
the conclusion that inasmuch as the microscope reveals no differ- 
ence in the structure there is really no structural difference 
between them, and that the only way in which the difference in 
action can be explained is by having recourse to the old hypo- 
thesis that the metamorphoses of matter, and the actions of force 
are in the living world regulated bya metaphysical entity termed 
a vital principle, and that dissimilar actions by similarly con- 
structed parts are only to be explained by referring them to the 
operations of this principle. After alluding further to the hypo- 
thesis of the vital principle and its supposed actions, and after 
stating that he did not follow the teaching of those who still 
adhere to this doctrine, the lecturer said that, viewed from the 
physical side, there appears to .be no reason for supposing that 
two particles of protoplasm, which possess a similar microscopic 
structure, must act in the same way; for the physicist knows 
that molecular structure and action are beyond the ken of the 
microscopist, and that within apparently homogeneous jelly-like 
particles of protoplasm there may be differences of molecular 
constitution and arrangement which determine widely different 
properties. 
A great change is now taking place in physiological tuition in 
this country—a superabundance of physiological anatomy, and 
an almost entire absence of experiment, are no longer the cha- 
racteristic features of our tuition. The study of physics, too 
much neglected, is happily now being more and more regarded 
as important in the preliminary training of the physiologist, 
NATURE 
I am not questioning” 
[Sez 25, 1873 
as the study of anatomy and of chemistry; and I trust that 
the day is not far distant when in our medical schools the 
thorough education of our students in mathematics and phy- 
sics will be insisted upon as absolutely essential elements 
in their preliminary education. Until this is done physiolo; 
will not advance in this country so rapidly as we could wish. 
I would not in this place have alluded to a question concern- — 
ing medical education, but for the fact that the progress of physi- 
ology will always greatly depend upon the education of medical 
men, for only those who are conversant with physics and chemis- 
try, and who, in addition, are acquainted with the phenomena 
of disease—that is to say, with abnormal physiological conditions 
—can handle physiology in all its branches. Physiology owes 
not a little to a study of pathology—that is, of abnormal physio- 
logical states. The study of a diseased condition has, on several 
occasions, given a clue to the discovery of the function of an 
organ. Nothing was known regarding the function of the spleen — 
until the pathologist observed that an increase in the number of 
white corpuscles in the blood is commonly associated with an 
enlargement of this organ. Hence arose the now accepted doc- _ 
trine that the spleen is concerned in the growth of blood cor- 
puscles, The key to our knowledge of the functions of certain 
parts of the brain has also been supplied by a study of the 
diseased conditions of that organ. The very singular fact that 
the right side of the body is governed by the left, and not by the 
right side of the brain, was ascertained by observing that palsy 
of the right side of the body is associated with certain diseased 
conditions of the left side of the brain. That the corpus striatum 
is concerned in motion, while the optic thalamus is concerned in © 
sensation ; that intellectual operations are manifested specially 
through the cerebral hemispheres, are conclusions which were 
indicated by the study of diseased conditions. Moreover, by the 
pursuit of the same line of inquiry the key has been given to the 
discovery of many other facts regarding the brain functions. 
Some years ago M. Broca made the remarkable observation that, — 
when a certain portion in the front part of the left side of the 
brain becomes disorganised by disease, the person loses the 
power of expressing his thoughts by words, either spoken or 
written. He can comprehend what is said to him, his organs of 
articulate speech are not paralysed, and he retains his power of 
writing, for he can copy words when told to do so, but when he 
is asked to give expression to his thoughts by speaking or by 
writing, or eyen to tell his name, he is helpless. With a palsy 
of a portion of his brain, he has lost his power of finding words 
—he has lost his memory for words ; and mark you, although he 
loses his power of finding words, his intelligent perception of 
what passes around him and of what is said to him is not lost. 
It is true that this condition of aphasia, as it is termed, has been 
found to exist when various parts of the brain have been diseased ; 
for example, it has been found to coexist with a diseased state of 
the posterior instead of the anterior part of the cerebrum. This 
fact rendets it very difficult as yet to assign a precise locality to the 
faculty of speech, It is not, however, my intention to discuss — 
this question, for my object is merely to show how the study of 
disease has given a clue to the physiologist. Broca’s observation 
led to the thought that, after all, the dreams of the phrenologists _ 
would be realised, in so far as they supposed that the various - 
mental operations are made manifest through certain definite 
territories of the brain. 
It has until lately been supposed that the convolutions of the 
cerebrum are entirely concerned in purely intellectual operations, 
but this idea is now at anend. It is now evident, from recent 
researches, that in the cerebral convolutions—that is, in the part 
of the brain which was believed to minister to intellectual mani- 
festations—there are nerve-centres for the production of volun- 
tary muscular movements in various parts of the body. It has 
always been taught that the convolutions of the brain, unlike 
nerves in general, cannot be stimulated by means of electricity. 
This, although true as regards the brains of pigeons, fowls, and — 
perhaps other birds, has been shown by Fritsch and Hitzig to * 
be untrue as regards mammals, These observers removed the 
upper portion of the skull in the dog, and stimulated small portions 
of the exposed surface of the cerebrum by means of weak gal- — 
vanic currents, and they found that when they stimulated certain 
definite portions of the surface of the convolutions in the anterior — 
part of the cerebrum, movements are produced in certain definite — 
groups of muscles on the opposite side of the body. By this new 
method of exploring the functions of the convolutions of the 
brain, these investigators showed that in certain cerebral conyo- 
lutions, there are centres for the nerves presiding over the muscles 
