The Interstitial Granules of Striated Muscle etc. 327 



They no longer stain with osmic acid. After a still greater loss of body 

 weight only a few small faintly-refractive liposomes are to be seen 

 (fig. 1) — these can be shown only with Herxheimer's solution. 



In the rat there is a very rapid decrease in the number, size, re- 

 fractive power, and staining-intensity of the liposomes. A well-fed rat 

 may. contain a large number of strongly-refractive liposomes in its 

 muscle fibers, many of which may be stained with osmic acid. After 

 a reduction in the body weight of 15 to 20 per cent only a few faintly- 

 refractive liposomes are usually left. After a reduction of 25 to 30 per 

 cent, it is often found that no hposomes at all can be demonstrated. 

 Every liposome has disappeared. 



During inanition the cardiac muscle fibers behave similarly to the 

 dark fibers of skeletal muscle. In extreme emaciation no liposomes 

 at all are to be found in the muscles of the rat. A few faintly-refractive 

 liposomes were found in the most emaciated cats examined. 



It is noteworthy that the liposomes lose the power to reduce osmic 

 acid some time before they disappear. They may be seen in fresh prep- 

 arations and stained in Herxheimer's solution long after the osmic 

 reaction is negative. There is presumably an early loss of oleic fat. 



Moulton and Trowbridge [1909] have shown that the connective 

 tissue fat of very fat beef animals contains a considerably greater per- 

 centage of olein than that of very thin animals. In the connective tissue 

 fat the olein is therefore removed to a greater extent than the other fats 

 when the animal is put on low rations. 



The remarkable sensitiveness of the liposomes in rat muscle to 

 the food supply undoubtedly accounts to a considerable extent for the 

 large variations one finds in animals gathered at random. It will be 

 shown, however, later that the quality of the food is a factor of almost 

 as much importance as the quantity. A rat whose body weight has been 

 reduced 25 to 30 per cent, may develop a large number of deeply- 

 staining liposomes in its muscle fibers (if fed on a diet largely composed 

 of fat meat) tho the body weight remains far below normal. 



There is, as has been shown, a marked difference in the number 

 and character of the liposomes of a well-nourished normal animal and 

 those of an emaciated animal ; but the liposomes of an animal in ordinary 



