OF THE CAPILLARY VESSELS. 



the organs would be homogeneous; there would be but one 

 organ. This organic simplicity is only to be met with, on the 

 contrary, in animals deprived of vessels. 



383. The amount of the sanguineous capillary vessels, and 

 their proportion with the solid and non-injectable substance, 

 are not less interesting than their disposition in the several 

 parts of the body. 



The cellular tissue can not be injected. The epidermis, the 

 horny parts, the hair and teeth, are not injectable at all. The 

 adipose lobules are surrounded with a very fine vascular net- 

 work. Cartilages experience no change whatever by injec- 

 tion. 



The serous and synovial membranes are but slightly red- 

 dened by injection, but the masses and the fringes of adipose 

 matter are surrounded with a very beautiful vascular net- 

 work. The skin is the most vascular part. The matter of 

 injection sometimes transuded beyond the dermis into the 

 mucous layer or corpus mucosum. The capillary vessels of 

 the skin, which are at first of the first and second magnitude, 

 acquire the greatest degree of tenuity in penetrating into the 

 papillaB. The recent skin, immediately after being injected, is 

 much more coloured at its external surface; it appears equally 

 coloured throughout, when the uninjectable parts which con- 

 cealed the vessels have disappeared in consequence of desic- 

 cation. The cutaneous and mucous follicles are furnished 

 with a very loose vascular net-work. This is also the case 

 with the microscopic alveoli of the mucous membrane of the 

 stomach and intestines. The papillae of the mucous membrane, 

 like those of the skin, are furnished with an infinite number 

 of capillary vessels, which is also the case with the villosities, 

 at least their adherent extremity. The mucous membrane, 

 in general, is still more injectable than the skin, that of the 

 lungs, particularly, is so in the highest degree. The mem- 

 brane of the pituitary sinuses is much less so than the rest. 

 The conjunctiva reddens moderately, and less by injection 

 than by inflammation. The mucous membrane of the excre- 

 tory ducts, and the glands themselves, are provided with nu- 

 merous capillary vessels. 



