HYDROCARBONACEOUS SUBSTANCES. 



67 



FIG. 6. 



border of large oil-globules ; but appear by transmitted light only as 

 minute granules. The white 

 color and opacity of the chyle, 

 as of other fatty emulsions, de- 

 pend upon this molecular condi- 

 tion of the oily ingredients. The 

 albumen and salts, which are in 

 intimate union with each other, 

 and with the water, would alone 

 make a colorless and transparent 

 fluid ; but the oily matters, sus- 

 pended in distinct particles, with 

 a different refractive power from 

 that of the serous fluid, interfere 

 with its transparency, and give 

 to the mixture its diffused white 

 color. The oleaginous nature of 



the particles is shown by their CHYLE, from commencement of Thoracic Duct, from 



the Dog. 



solubility in ether. 



In milk the oily matter occurs in larger masses, or " milk-globules," 

 which have an average diameter of 6 mmm. They are not quite fluid, 

 but have a pasty consistency, owing to the large quantity of palmitine 

 which they contain, as compared with the oleine ; and under the 

 microscope they present accordingly a somewhat irregular outline. 

 By heating the milk they may be completely liquefied, and made to 

 assume a globular form. When forcibly beaten into a mass by churn- 

 ing, they constitute butter. 



In certain parts of the body oil-drops and granules are deposited in 



the substance of cells or other ana. 

 tomical elements ; as in the laryn- 

 geal, trachea!, and costal carti- 

 lages, and the secreting cells of 

 the sebaceous glandules. Oily 

 matter also occurs, under the same 

 form, in the glandular cells of the 

 human liver, where it is a con- 

 stant ingredient in a state of 

 health. In certain cases of dis- 

 ease it accumulates in excessive 

 quantity, producing a fatty de- 

 generation of the organ. 



In the carnivorous animals it 

 exists normally in the epithelium 

 cells of the convoluted portion 



GLOBULES OF Cow's MILK. . 



or the urmiferous tubules. The 



drops and granules are here so numerous as often to fill, apparently, the 

 whole calibre of the tubules. 



FIG. 7. 



