112 REPORT—18638. 
at the elbow; well-marked instances of similar interdependence of joints were 
to be found in other parts of the horse, and also in other animals—e. g. in the legs 
and wings of birds. He proceeded to show that movements of that description 
in the humeral region of the horse were exactly those most frequently and usefully 
employed by human beings; that the shoulder and elhow were usually flexed 
and extended together; that likewise in walking, leaping, &c., flexion and exten- 
sion of the hip, knee, and ankle went together; that in those movements the 
long muscles were not alternately contracted and extended, but kept in a state of 
medium contraction, very slightly altering their length, and were, therefore, evi- 
dently not the muscles which produced those movements. On the other hand, it was 
shown that a muscle passing over two joints, if maintaining a definite length, would 
cause another muscle passing over only one of them to act upon both. It was 
argued that, in the movements referred to, the long muscles gave force, but not 
velocity. 
Note on the Change of Attitude which takes place in Infants beginning to Walk, 
By Dr. Crevanp. 
This paper was illustrative of two drawings traced from a mesial section of the 
body of a newly born child. One of the drawings showed the position of the ver- 
tebral column when the head was bent forwards, and the thighs flexed upon the 
body; the other its position when the body was stretched straight with the thighs 
in a line with the trunk. It was shown that the vertebral column of the newly 
born child was capable of being curved in any direction in its extent above the 
sacrum, but that the sacral concavity forwards was already formed. The limbs, 
however, could only be made to lie in a straight line with the trunk by bending 
the pelvis back, so as to develope the lumbar convexity forwards of the column. 
Thus the straightening of the limbs when the child begins to walk was shown to 
be effected not by mere motion of the pant but by development of the lumbar 
convexity of the vertebral column. In the drawing of the stretched body the brim 
of the pelvis was vertical; in the other drawing it was 52° removed from being in 
a straight line with the lumbar vertebree immediately above it. 
Some Observations on the Eggs of Birds. By Joun Davy, M.D., F.RS., Se. 
The author, after pointing out certain qualities of resemblance common to the 
eggs of different kinds of birds, such as especially the alkaline nature of the albu- 
men and the acid of the yelk, and that the two are in opposite electrical conditions, 
described the results of the experiments he had made to endeavour to ascertain in 
what respects the eggs of different species differ. Some of the conclusions which 
his results seem to warrant are the following :— 
1. As to the colour and markings of eggs, these are so very various, that the 
colouring-matter is of an organic kind very similar to that of leaves and flowers, 
and in part depends on molecular arrangements. 
2. That the albumen in quantity greatly exceeds the yelk, but in eggs of differ- 
ent species in no regular manner, whilst in all the quantity of solid matter in the 
yelk is proportionally much larger than in the white. 
3. That the temperature at which the coagulation of the albumen takes place 
varies in almost every instance, and that the firmness of the coagulum does not 
appear to be regulated by the proportion of solid matter which the albumen yields 
on evaporation. 
4. That the coagulum of each has an aspect of its own, varying in different 
instances as to tint and degree of translucency, and in some varying in colour. 
The author, taking into consideration the many sources of error to which experi- 
ments on eggs are exposed, offers his results, and the conclusions from them, merely 
as approximations. 
Some Observations on the Blood, chiefly in relation to the question, Is Ammonia 
one of its Normal Constituents? By Joun Davy, M.D., F.RS., 6. 
Of the many questions relating to the blood, there are two, the author observed, 
