STORAGE OF FAT IN MUSCULAR TISSUE OF KING SALMON. 121 



the fat in the fibers. Mahalanobis considers the fat deposition as a "fatty infiltration 

 due to increased accumulation of fat from diminished utilization in the tissues."" In 

 the same paragraph he says:'' "Figure 3 is from a fish fresh from the sea — one that had 

 been actively feeding, and consequently its blood and lymph were rich in fat, whence, 

 in all probability, the muscle cells absorbed fat and stored it between the fibrils." And 

 "as already pointed out, the fat granules in fish leaving the sea are more crowded imme- 

 diately under the sarcolemma (fig. 3, pi. iii)." These quotations include all the remarks 

 tending to show the author's views as to fat transferences in the salmon tissue. It is 

 evident that he has given attention only to the mechanism whereby the fat is originally 

 laid down in the muscle, and his conception is that the process is one of "infiltration" or 

 absorption from the blood and lymph. 



Mahalanobis is hopelessly confused in his studies by the fact that he has failed to 

 recognize the dissimilarity of two strikingly different tissues. This is shown in the follow- 

 ing quotation and by the figures referred to therein: "In the fish leaving the sea this 

 accumulation of fat in the fibers sometimes reaches an enormous amount, and a thick 

 layer occurs under the sarcolemma. This will be evident from a comparison between 

 figure 2 and figure 3, the former being from a late fish, no. 69, and the latter from no. 79." '^ 

 The figures given by him exhibit differences both in structure and in fat disposal which 

 bear no relation either to the seasonal type or to the stage of fasting which Mahalanobis 

 observed, as the studies presented here on the king salmon conclusively show. The 

 basis of this matter is more fully discussed in this paper in connection with the descrip- 

 tion of the tissues in question. Mahalanobis compared the dark muscle fiber of his fish 

 no. 79 with a pink fiber of no. 69. The former muscle is normally loaded with enor- 

 mous fat droplets in the fiber, whereas the latter muscle never has fat in larger size than 

 liposomes. His figure 3 from fish no. 69 is from the intermediate zone of pink fibers. 

 Had he chosen a deeper group of fibers the dearth of fat would have been undoubt- 

 edly greater. The figures are illustrative of the two normal extremes, are from wholly 

 different types of muscle, and are, therefore, not directly comparable. This fact he appar- 

 ently fails to recognize, though his first quotation from Miescher should have helped in 

 the identification of the muscle types he used. 



On the comparative side of the question involved here the recent brilliant work 

 of Bell should be presented.'* Bell has studied the liposomes in the muscle fibers of the 

 ox, dog, cat, rabbit, rat, and the frog. He has also examined the moth (Phlcgethontius), 

 and the fly (Musca). He presents a good historical statement of the work that has' 

 been done along this line, from the discovery of interstitial granules of muscle fibers by 

 Henle in 1841, down to the publication of his own work in 191 1. Bell calls the muscle 

 interstitial granules that are of a fatty nature "liposomes," a term introduced by 

 Albrecht. 



Bell, in discussing the granules in the muscle fibers, says (p. 310), "All agree with 

 Kolliker that the granules lie in the sarcoplasm between the fibrils," and later: 



In the skeletal muscles of vertebrates, when the cross markings are wide and distinct, it can usually 

 be seen that the granules occupy the J-band. But when the striations are narrow the granules seem to 

 extend the entire distance between adjacent Krause's membranes. Large granules nearly always lie 



<^ Paton, op. cit., p. 110. 

 ^ Paton, op. cit., pi. I. 



* Mahalanobis, op. cit., p. 108. His fish no. 79 was "a fish fresh from the sea." 



d Bell, E. T.: The interstitial granules of striated muscle and their relation to nutrition. Internationalen Monatschrift fiir 

 Anatomic und Physiologic, bd. xxvni, s. 297, 1911. 



