August, 1913. 



KNOWLEDGE. 



287 



paler and show well-marked scaling and an ill-defined 

 medulla. 



The Russian bear also shows the two kinds of 

 fibres, but the medulla, when present, is much more 

 pronounced. 



In the hairs of the sloth bear the medulla is usually 

 absent. The pigment is deposited in lines in the 

 same way as in the hair of the other bears, while in 

 the central portion of the fibre the scaling is close 

 and well marked. 



Hairs of very distinctive types are shown by the 

 kangaroo (see Figure 312) and the rabbit (see 

 Figure 313), the structure of the medulla and the 

 scaling being very characteristic in each case. 



A single example of the hair of the antelopes is 

 given (see Figure 314) which shows two portions 

 of a fibre from the coat of a Rhodesian sable 

 antelope. The hairs are long and coarse and show 

 a broad opaque medulla extending from the base 

 nearly to the tip (A). The scaling on the cortex is 

 fine but well defined. 



There is no difficulty in distinguishing between 

 human hair and the hair of any of the lower animals, 

 but the numerous points of resemblance between the 

 hairs of allied species of animals suggested the 

 possibility that man's nearest relation among the 

 animals might also show analogous resemblances to 

 human hair. 



Apart from its scientific interest, the point is of 

 practical importance, since it is frequently necessary 

 in forensic w^rk to ascertain whether a particular 

 hair belonged L o a human being or to an animal. 



To investigate this question we have made a study 

 of widely differing types of human hair, and have 

 compared them with the hair of some of the principal 

 species of anthropoid apes. 



The hair shown in A, Figure 3 15, was taken from the 

 head of a newly-born female child, and it is remark- 

 able that the fibre has many more points of resem- 

 blance in common with the hair of some of the lower 

 animals such as the merino sheep, than are to be 

 found in adult human hair. Thus on the hair of the 

 young child (B) the scales are very scanty, while in 

 adult human hair they become more numerous and 

 more compressed. There is also a tendency towards 

 a jointed structure, which disappears in the hair of 

 the adult (see C, Figure 315). 



In the hair of the young chimpanzee (see 

 Figure 316) it will be noticed that one of the fibres 

 (B) resembles the hair of the young human child, 

 with the exception that the scaling is less pronounced ; 

 but in the other fibre (A) there is a clear medulla. 

 Again, in the hair of the old chimpanzee (see 

 Figure 317) it will be seen that part of one of the 



fibres, near the base, resembles adult human hair, 

 but that here, again, the scaling is less pronounced 

 than on human hair. In this hair, however, a 

 medulla interrupted in places will be found, while 

 at the top the disposal of the pigment differs from 

 that usually found in human hair. 



The hair of the orang utan (see Figure 318) 

 and of the gibbon (see Figure 319) also shows 

 points of resemblance to human hair, but there are 

 also many distinguishing features. 



A medulla is much more common in the hair of 

 the higher apes than in European human hair. In 

 a lecture to the Selborne Society it was stated by- 

 one of us (Mitchell) that apparently a medulla 

 was not formed in human hair. 



Since then our investigations have led us to 

 modify this statement considerably. 



It occurred to us that since the axillary hair in 

 man is probably a vestige of his former ancestry, it 

 was in such hair that a medulla would be most 

 likely to be found. This was confirmed by a 

 study of the hair from the human arm-pit (see 

 Figure 320). In some of these hairs there was a 

 narrow irregular medulla (A), with dots of pigment, 

 but no scaling visible, while others equally stout 

 showed no medulla, but were covered with fine 

 scaling which was well marked near the base. 



The remarkable result of this examination led us 

 to examine the hair of a negro, in which it appeared 

 probable that the relationship between the hair of 

 man and the apes might be traced more closely than 

 in the case of European human hair. The result is 

 shown in Figure 321. 



The fibres were coarse, and usually showed a 

 narrow medulla, which in some cases was continuous 

 throughout the whole length of the hair. 



The pigmentation was so pronounced in some of 

 the fibres as almost to obscure the tract of the 

 medulla, while other hair contained a much smaller 

 amount of pigment. Apparently the amount of 

 pigment had no bearing upon the occurrence of a 

 medulla. In all the fibres the scaling was ill-defined. 



A comparison of these hairs with the hair of 

 the apes, especially the orang utan, shows how 

 close are many of the resemblances. In fact, 

 it appears justifiable to conclude that the hair of the 

 negro resembles that of some of the higher apes 

 much more nearly than it does the hair of the 

 average European. 



We intend to continue the study of this interest- 

 ing branch of our subject, and should be grateful if 

 any reader of " Knowledge " would forward to us 

 any authenticated specimens of hairs of out-of-the- 

 way races of mankind. 



Note.— All the illustrations are drawn to the same scale of magnification (104 diameters). 



