1 Ocr., 1899,] QUEENSLAND AGRICULTURAL JOURNAL. 357 
produce no fresh hair bulbs after the animal is born. Every hair root that is 
likely to come to maturity and produce a healthy hair has been fornied at an 
early period. It is hence impossible to increase the dense growth of the wool 
fibre, or, in other words, the numerical proportion of them to the square inch, 
by good feeding. Plentiful nourishment will tender to foster the growth of each 
existing hair, but it does not Pres uee new hair bulbs. Density of growth is, 
therefore; a peculiarity of the race, a result of breeding, not of feeding. 
Bischoff has confirmed Cuvier’s statement, and he has siven some valuable 
information about the change of primitive cells of the epiderm and the cutis 
into the so-called hair bulbs.  Bischoff’s observations were chiefly made on 
embryos of rabbits, and Reissner finally collected, compared, and sifted all the 
information that could be obtained. “He deseribes + e origin of the hair as 
follows:—As soon as the embryo has so far developed that we can clearly 
distinguish the epiderm from the cutis, both begin to thicken at the same place. 
First Stack or DEvELOpMENT— 
a. Undifierentiated epiderm. 
b, Hill-shaped accumulation of epidermal cells. 
ce. Corion or dermis. 
Srconp StacE— 
a, Undifferent epiderm. 
b. Increased growth of epiderm and first formation of process or 
apophysis of epiderm. 
ce. Globular accumulation of dermis papillz. 
d. Corion or dermis. 
The cutis recedes and the epiderm sends forward 
J a slender column of cells 
which forms the sheath of the future hair. ee 2 
THIRD STaGE— 
a. Cuticle. 
6. Corion or dermis. 
c. Papilla. 
FourtH Stace— 
ef. Cylindrical apophysis or process of epiderm, 
e. The external portion will be changed into a sheath for the hair. 
f. The internal portion is light-coloured; the external portions of 
it will form the inner part of the sheath, and the central parts 
will be changed into the hair-shaft. 
ce. Papilla. 
d. Part of bulb. 
At the place where this process from the epiderm x, 
: i : eaches the cutis, the 
cells of both epiderm and cutis combine and form a small conic body—the hair 
bulb. 
First DEVELOPMENT OF THE HaAIR-SHArT AND rts SHEATH— 
a. Central cells. : . 
b. Layer of cylindrical cells of the process of the epiderm, 
ce. Basement membrane. 
d. Papilla. 
e. New cells of the papilla destined for the formation of “aN hair. 
FurtHEerR DEVELOPMENT OF HAIR-SHAFT AND SHEATH— 
a, Differentiated epiderm. 
b, Central contents. ; 
ce. Layer of cylindrical cells of process or apophysis of epiderm, 
d. Basement membrane. 
e. Papilla. 
f. Beginning of the formation of internal fibrous membrane, 
g. Central cone, not yet differentiated into hair-shaft and its sheath, 
