76 



KNOWLEDGE 



[April 1, 1899. 



varies considerably in different individuals, and from our 

 own observations appears larger and better developed in 

 the negro races. The muscle called the erector pili, from 

 its attachments, has long been recognized as having an 

 influence on the position of the hair, causing its erection 

 by pulling forward the root of the hair, thus converting 



Negro, Adult. 



iVegro Pectus, 9th Montli. 



Fio. 6. — Sections showing appearauce of the hair follicles iu 

 straight, wavv, and curly hair. 



the shaft into a lever, the fulcrum of which corresponds 

 to the dense stratum corneum through which it passes to 

 appear on the surface. Such action of these little muscles 

 is displayed when a cat in rage erects the hair of its tail, or 

 a straight-haired dog causes the hair of its back to rise in a 

 median crest (Fig. 5). Their influence in man is commonly 

 observed in the condition known as "goose skin." Further, 

 it is to be noticed that the gland is always placed between 

 the muscle and the hair shaft, thus occupying the 

 triangular interval between them, so that during the 

 action of the muscle the gland must necessarily be 

 subjected to pressure, aiding thereby the expulsion of its 

 contents. 



As has been already stated, straight hair is always 

 circular in section, and is usually thicker than curly hair, 

 which is ribbon-like and fine, the finest human hair 

 being that met with in the Bush and Andaman races. 

 Now it appears to us that these facts have a most im- 

 portant bearing on the question under consideration. In 

 order that the muscle afore-mentioned may act as an 

 erector of the hair, it is necessary that the hair must be 

 sutticiently strong to resist the tendency to bend ; unless 

 this be so, the lever action is at once destroyed. On the 

 other hand, when the hair is fine and ribbon-like, the 



shaft, no longer sutKciently stout to resist the strain of 

 the muscle, naturally assumes a curve, and this, we think, 

 is the explanation why the follicle assumes the form so 

 well displayed in the section of Bush scalp represented 

 in Figs. 1 and 6. The influence of the sebaceous 

 gland on this curvature must not be overlooked. If a 



scalp, in which the follicles 

 are curved, be examined, the 

 gland is seen to be placed on the 

 concave surface of the curve, and 

 the muscle is attached to the 

 same side of the follicle just be- 

 low the gland ; the gland, there- 

 fore, forms a mass of greater 

 resistance around which the 

 follicle may be curved by the 

 traction of the muscle, thus lead- 

 ing to the characteristic form of 

 the follicle met with in races 

 with curly hair. At the same 

 time it may be noticed that the 

 base of the follicle is often 

 hooked backwards, as may be 

 seen in the Bush scalp (Fig. 6), 

 and this, presumably, must be 

 accounted for by its vascular 

 connections, which are here best 

 developed, and which will tend 

 to withstand the strain exercised 

 by the muscle. The follicle thus 

 becoming more or less per- 

 manently curved, it naturally 

 follows that the softer cells at 

 the root of the hair will accom- 

 modate themselves to the curve, 

 and becoming more homy in 

 their consistence as they advance 

 to the surface, will retain the 

 form of the follicle in which 

 they are moulded, the cells 

 on the concave side of the 

 hair being more compressed 

 than those on the convex side. 

 In this way we have, in all 

 probability, a more reasonable 

 curliness in the hair is produced 



Negro Fa>tus, 5th Month, 

 the scalps of races with 



explanation of how 

 than any hitherto offered. 



There are other considerations which might be men- 

 tioned in this connection, but these are beyond the scope 

 of the present article. 



-♦- 



THE LOVE-GIFTS OF BIRDS. 



By Ch.^les a. Witchell. 



APRIL and May are the chief months in which wild 

 birds are nesting ; and in these months the birds' 

 small property is most heavily taxed by collectors. 

 All but a minute fraction of this waste of egg-life 

 is useless. But this is an old theme. The 

 remark might be permitted, however, that in the treatment 

 of wild birds the country should learn from the city, 

 where public ornithology rises above the use of the gun, 

 and knows how to tame as well as how to kill. It might 

 be of benefit to the sportsman who goes to the seaside 

 armed with a gun if he were to stand for five minutes on 

 the Embankment, or on the bridge in Regent's Park, to 

 see the gulls fed. 



In some earlier articles in Knowledge I have endeavoured 

 to prove to the person who is developing an interest in 



