12 OBSERVATIONS ON THE 
The muscles are seen to arise in all cases from the most superficial part of the 
corium, and to pass down obliquely to their insertions into the hair-follicles 
immediately below the sebaceous glands. It will be remarked that the muscles 
are here all on the same side of the respective hair-follicles, viz. on that side 
towards which the hair slopes: and such I found in the examination of a large 
number of sections to be always the case. This is an interesting fact, as such 
an arrangement of the muscles is exactly that which is best adapted for erecting 
as well as protruding the hairs, which must be drawn by their contraction 
nearer to the perpendicular direction. That this erection as well as protrusion 
of the hairs does occur, I have proved by artificially exciting the state of cutis 
anserina upon my own arm and leg. Tickling a neighbouring part will often 
induce horripilation, and if the eye is kept on an individual hair at this time, 
it is seen to rise quickly as the skin becomes rough, and to fall again as the 
horripilation subsides. I have never seen more than one muscle to each hair- 
follicle in the scalp ; and in order that a single muscle may by its contraction 
simply erect a hair, it must be placed in a plane perpendicular to the surface 
of the skin and parallel to the hair; this explains the fact before alluded to, 
that a section made in such a plane is sure to contain the muscles in their entire 
length if at all, while sections in other planes cut across either the muscles or 
the hairs. 
Fig. 2 represents the superficial attachments of the two muscles a, and a, 
of Fig. r ; abeing the upper end of a,, and 0 that of a,; c is the corneous, and 
d the mucous layer of the epidermis ; the intervening tissue between the muscles 
was omitted in the sketch to save time. 06 furnishes a good example of the 
subdivision of a muscle into secondary bundles near the surface, as observed 
by Henle, while in a the subdivision, if it has occurred at all, is certainly not 
carried so far: the muscle bc in Fig. 4 seems not to have undergone any sub- 
division: in some cases a simple bifurcation of a muscle near the surface is 
all that is seen: hence the splitting up of the muscles into smaller bundles 
near their upper attachment appears not to be a constant thing, and when 
it does occur, exists to a very variable degree in different muscles. Want of 
room in the plate has rendered necessary so great a reduction of the scale? 
from the original drawing, as barely to allow the nuclei of the muscles to be 
perceived ; by looking closely, however, it may be seen that at e and / nuclei 
exist immediately under the epithelium, and before introducing them into the 
sketch, I ascertained, by a higher power, that they were really of the same 
character as those in other parts of the muscles. At g it was impossible to 
trace the nuclei so far ; 1f any existed here, they were obscured by the fibrous 
’ Figs. 2, 3, and 4 have all been reduced one-half from the original sketches. 
