IS THE BODY A MACHINE ? 



33 



minute droplets. Although these droplets are of 



microscopic size they are not actually in solution, 



and therefore not subject to the force of osmosis 



which only affects solutions. The osmotic force 



will not force fat drops through membranes, and 



to explain their 



passage through 



the walls of the 



intestine requires 



something addi- 



tional. We are 



as yet, however, 



able to give only 



a partial explan- 



ation of this mat- 



ter. The inner 



wall of the intes- 



tine is not an in- 



ert, lifeless mem- 



brane, but is 



made of active 



bits of living mat- 



ter. These bits 



of living matter 



appear to Seize 



hold of the drop- 



We nf /->;! KTT 

 Oll Dy 



means Of little FIG. 5. An enlarged figure of four cells of 

 processes which t ^ le membrane B in Fig. 4. The free 

 *V " 



ley 1 OUt, 



and then pass 

 them through their own bodies to excrete them 

 on their inner surface into the blood-vessels. 

 Fig. 5 shows a few of these living bits of the 

 membrane, each containing several such fat drop- 

 lets. This fat absorption thus appears to be a 



FIG. 4- 



FIG. 5. 



FIG. 4. Diagram of a single villus en- 

 larged. Z? represents the membranous 

 surf ace covering the villus ; C, the blood- 

 vessels within the villus. 



surface is at a; /"shows fat droplets in 

 process of passage through the cells. 



