84 PHILOSOPHICAL TRANSACTIONS. [aNNO 1 696'. 



absorbed, the remains, being merely excrementitious, are only fit to be ex- 

 clufled by stool. 



The analogous white appearance of the chyle, whether in the stomach, 

 or intestines, and always in the lacteals, and thoracic duct, may be seen in the 

 commixtures of divers liquids, which apart exhibit no such appearance : nor is 

 this phenomenon any otherwise than a transposition of particles ; whether by a 

 menstruum insinuating into them, and dividing them into gross globules, as an 

 acid into a sulphur, or vinegar with oil, &c. or else by precipitation, as when a 

 gummonsor resinous body is dissolved in a spirituous menstruum, and mixed 

 with a phlegm ; so tincture of myrrh and benjamin, &c. make a milky appear- 

 ance in common water.* 



The longitudinal and transverse orders of fibres of the guts are the instru- 

 ments by which their peristaltic motion is performed: which motion is not only 

 necessary for propelling their contents ; but by the reciprocal contraction of 

 those muscular fibres of the guts, and apposition of their connivent valves, 

 the mouths of the lacteals are disposed to receive what is prepared for them : 

 hence it is, that we can by no means make any fluid whatever pass from the 

 cavity of the guts into those lacteals, in a dead animal. A further use of this 

 contraction of the muscular fibres of the intestines, is to accelerate the chyle 

 in its progress in the lacteals, till the lympha derived from the extremities of 

 the arteries of the guts mixes with it ; which conjunction is made in the lacteals, 

 before they leave the external surface of the intestines. By this means the pro- 

 gression of the chyle is made towards the mesenteric glands, into whose cells 

 it is received, and where it again mixes with a juice conveyed by the arteries of 

 each gland ; which juice, or lymphatic liquor, not only further dilutes the 

 chyle, like that from the- arteries of the intestines, but adds a fresh impetus, 

 by which its motion is further promoted through the lactea secundi generis, 

 arising out of each mesenteric gland, and discharging their contents into the 

 receptaculum chyli. Here the chyle mixes with the lympha, sent through the 

 lymphaeducts from the inferior limbs and neighbouring parts ; by which the 

 chyle is not only further elaborated, but its ascent into the thoracic ducts is 

 promoted, whose several divisions and inosculations, like the veins of the tes- 

 ticles, with its many valves, looking from below upwards, and its advaniagcous 

 situation between the great artery and vertebraa of the back, together with the 

 lymphaeducts, discharging their lympha derived from the lungs and neighbour- 

 ing parts of the thorax, demonstrate the utmost art, in order to promote its 



* This chyemical view of chylification coincides, in some respects, with that given by the late Dr. 

 G. Fordyce, in his excellent Treatise on Digestiou. -j 



