318 DIGESTION. 



correct. This observer, having tried all methods of artificial 

 injection of the lacteals of the villi, came to the conclusion 

 that nothing was to be learned from examinations of the 

 mucous membrane after death. He then examined the villi 

 of a dog in which the entire lacteal system was engorged 

 with chyle, securing the chyle in the parts by ligatures 

 applied to the principal trunks. "When he examined the 

 mucous membrane, he found it white, as though it had been 

 sprinkled with milk, and the villi engorged and in a sort of 

 erection. On placing some of these villi between two plates of 

 glass and examining them with a magnifying power, he saw 

 them divide, while under observation, into two portions ; a 

 peripheral portion, occupied by loops of blood-vessels, and a 

 central, white portion, which had a cylindrical or ellipsoidal 

 form. It is this central portion which has been taken for the 

 single lacteal by most anatomists ; but Sappey believes that 

 this is an illusion ; and that the white appearance is produced 

 simply by the pressure of the glass forcing the chyle which 

 is in the peripheral portion out of the villus, while the fluid 

 is imprisoned in the central portion. The figures given by 

 Kolliker certainly have the appearance described by Sap- 

 pey ; and if the lacteals really commence by a single dilated 

 vessel, they have no analogue in other parts of the lymphatic 

 system. 



Sappey, while unable to demonstrate lacteals in the intes- 

 tinal villi, infers their existence from analogy with the papillae 

 of various parts. The reason why they cannot be injected in 

 the intestine is because the soft tissue in which they are em- 

 bedded affords no support to their walls. As regards their 

 mode of origin, we are disposed to adopt the opinion of 

 Sappey, that they commence by a delicate anastamosing 

 plexus situated outside the blood-vessels. 1 This is the way 

 in which lymphatics have been shown to arise in the papillae 

 of the skin and other parts in which the density of the sur- 



1 SAPPEY, op. cit.,tome iii., p. 149 et seq. 



