126 SPECIAL HISTOLOGY. 



below 7 years of age, for example, the cutis is, according to 

 Krause, only half as thick as in the adult, until at last, though 

 at a time which is as yet undetermined, the new development 

 of cells ceases, as at a later period, perhaps, does the extension 

 of those elements, cells, fibres, &c, which are already formed. 

 The fat-cells of adults, in which the process of growth is 

 especially obvious, according to Harting, are in the orbit twice, 

 in the palm three times as large as in the new-born infant ; 

 whence it results, that they increase in size in proportion to 

 the parts of the body to which they belong. 



[In embryos of two months the skin is 0006 — 001'" thick, 

 and wholly composed of cells. At the third month it is about 

 006'", and already presents tolerably distinct connective tissue. 

 In the fourth month the first lobules of fat appear, and the 

 ride:es of the hand and sole of the foot. From the seventh 

 month onwards the panniculus adiposus is rapidly developed, 

 and at birth it is relatively thicker than in the adult.] 



§ 39. 



Physiological Remarks. — If we attempt to harmonise the 

 anatomical data here brought together, with the phenomena of 

 sensation exhibited by the skin, we meet with considerable 

 difficulties. The more intimate anatomy of the skin, as it is 

 here detailed, fails to demonstrate nerves in all the papilla?, or 

 even in the majority of them ; and yet experiment teaches that 

 though all points of the skin may not feel with the same deli- 

 cacy, they are all nevertheless sensitive. I hoped to be able to 

 submit Wagner's doctrine of the absence of nerves in many 

 papilla? to experimental proof, by examining the sensitiveness 

 of various parts of the body with the finest possible English 

 sewing needle. At first I really thought that I had found 

 some places which were quite insensible, whilst in others 

 the slightest touch produced sensation ; but on carrying the 

 investigation further, it appeared that the very same place was 

 often sometimes sensible, sometimes not ; so that, finally, I 

 came to the conclusion that the very smallest portions of the 

 skin are sensitive. But since even in the palm of the hand 

 the papillae containing nerves are widely dispersed, and in other 

 places occur but rarely or even not at all, it only remains 



