608 VI. OCCURRENCE OF LIPIDS IN THE ANIMAL 



cells which possess a characteristic structure entirely distinct from the 

 fibroblasts of the connective tissue. Moreover, the specific gland-like 

 structure of the brown adipose tissue has been demonstrated histologically 

 by Maximow and Bloom. 403 



Further proof of the characteristic nature of deposit fat is afforded by 

 experiments with embryonic tissue. Hausberger 404 demonstrated that, 

 when primitive "fat organs" from the embryonic tissue of rats were trans- 

 planted into adult animals, typical fatty tissues developed from them. On 

 the other hand, negative results were obtained when embryonic connective 

 tissue was transplanted in a similar manner. The embryonic adipose and 

 connective tissues were indistinguishable morphologically, and could be 

 recognized only by their location and development. 



There is also evidence that adipose cells belong to the reticuloendothelial 

 system which, of course, is not the case with cells in the connective tissue. 

 Thus, adipose tissue cells in the unfatted fat organ have a gland-like struc- 

 ture similar to that of the reticuloendothelial cells, and fat tissue has an 

 affinity for such cells. 405 The two tissues have similar functions. More- 

 over, the ability of omental cells to form antibodies is apparently correlated 

 with the occurrence of aggregates of reticuloendothelial cells. 406 In addi- 

 tion, Wasserman 405 has shown that, under certain conditions, adipose tissue 

 cells may reestablish their function of blood formation. This is in line 

 with the behavior of bone-marrow, the cells of which may exhibit both fat 

 storage and blood-forming functions. Vital dyes such as trypan blue are 

 stored equally well by the cells of the two types of tissue. 407-409 Adipose 

 tissue cells are able to take up these dyes especially well when they are 

 depleted of fat. These data lead one to the conclusion that adipose and 

 connective tissue differ, and also that the adipose tissue cells are capable 

 of functions other than that of fat storage. 



(2) The Specific Innervation and Blood Supply of Adipose Tissue 



Although early investigators such as Hofmeister 410 and Rasmussen 411 

 were of the opinion that fat mobilization in adipose tissue is unrelated to 



403 A. A. Maximow and W. Bloom, Histology, 6th ed., Saunders, Philadelphia, 1952, 

 p. 73. 



404 F. X. Hausberger, Verhandl. Ges. f. Verdauungs- u. Stoffwechselkrankheiten, 14th 

 meeting, Stuttgart, Sept. 22-24, 1938, pp. 450-454 (1939). 



4 ° 8 F. Wasserman, Z. Zellforsch. u. mikroskop. Anat., 3, 235-328 (1926). 

 4 ° 6 B. Portis, J. Infectious Diseases, 34, 159-185 (1924). 

 4 » 7 G. C. Dogliotti, Z. Zellforsch. u. mikroskop. Anat., 8, 222-248 (1929). 

 «» J. L. Bremer, Anat. Record, 70, 263-281 (1938). 



409 A. W. McCullough, /. Morphol., 75, 193-201 (1944). 



410 F. Hofmeister; cited by E. Wertheimer and B. Shapiro, Physiol. Revs., 28, 451-464 

 (1948), p. 452. 



411 A. T. Rasmussen. /. Morphol, 38, 147-205 (1923). 



