36 



PHYSIOLOGY, 



1. Cuticle. 



2. Rete inucosura. 



3. Corpus papillare. 



4. Cutis vera. 



5. Cellular membrane. 



6. Faniculus carnosus. 



(There are in certain parts of the body, and especially in 

 animals, muscular fibres passing up through the cellular 

 membrane, and inserted obliquely into the cutis verq) as at 

 6 in the plate. These form the muscular web, or paniculus 

 carnosus. It is this which raises the feathers in birds and 

 which in the hedgehog and porcupine rolls up the body, and 

 erects the spines ; and by means of this, animals shake off 

 flies from their skin. 



28. The skin is defended from the action of moisture, and 

 is also \kept soft and pliant by an oily fluid, which is separ- 

 ated from the blood by numerous sebaceous follicles.^ We 

 find these the most numerous where there are folds of the 

 skin, or hairs, or where the surface is exposed to friction. 

 We sometimes see the oily matter secreted by these glands 

 assume a dark appearance, in the form of black specks, scat- 

 tered over the face, which are called by many worms, because 

 when pressed out they assume that aspect. 



29. The hair is usually treated of by physiologists as an 

 appendage to the skin, fine hair takes its origin from the 

 cellular membrane in the form of bulbs, each bulb consisting 

 of two parts ; an outer, which is vascular, and from which 

 the hair obtains its nourishment ; an inner, which is mem- 

 braneous, and which forms a sheath or tube to the hair during 

 its passage through the skin. ..The external covering of 

 each hair is of a horny structure, while the central part is 



