Development, &c., of the Fat-cell. By G. and F. E. Hog (/an. 363 



were too exclusive in their limitation to only one form of the 

 parent-cell. 



When, however, we pass from the mere expression of shape to 

 the opposite opinions held by different observers regarding the 

 essential nature of the parent-cells, we find it impossible either to 

 reconcile these opinions or to agree with any one of them. We 

 agree as little with Eanvier in supposing those parent-cells to be 

 special in their nature, as we do with Toldt in supposing that only 

 fat-cells can give origin to future fat-cells. Klein's idea of peri- 

 lymphangeal nodules developing into fat-tracts, and fat-tracts being 

 appanages of the lymphatic system, appears to us too far-fetched, 

 so that there only remains for us to discuss how far it is correct to 

 consider fat-cells as developed from the fixed cells of the connective 

 tissue or from the adventitia of blood-ves«els. 



What is the connective tissue, and what are its branched cells ? 

 These are questions which we admit we are unable to answer, 

 unless it be to the efiect that we believe both terms to be no longer 

 appUcable to the cells or tissue to which they were at one time 

 attached. 



The term connective tissue, since it was first applied by Johannes 

 Miiller, has been modified out of all its original meaning by succeed- 

 ing histologists, until at the present day no two histologists of 

 eminence are agreed upon what constitutes that tissue. 



Held at one time to include such structures as cartilage and 

 bone, in whose fixed cells no one ever supposed fat to be normally 

 developed, it is now almost confined to gelatinous, or what are 

 called fibrous tissues in general, such as tendons, tbe subserous and 

 subcutaneous tissues, &c. For our part, even if we acknowledge 

 the branched cells in tendon, the cornea, and similar structures to be 

 fixed cells, yet here also no one supposes that they can normally 

 become fat-cells ; and as regards the subcutaneous and subserous 

 tissues in which fat-cells are generally found, we cannot admit that 

 the branched cells found there are anything other than wandering 

 cells, moving through the soft gelatinous matrix to enter into the 

 formation of blood-vessels, fat-cells, or any of the other definite 

 fixed cells found there, or leaving them in retrogression when that 

 phase supervenes. Even should the term connective tissue be 

 retained for the matrix or tissue referred to, we must hold the term 

 fixed branched cells to be incorrect and inapplicable, and so far we 

 are at variance with Flemming, Klein, and others, who speak of 

 these as fixed branched cells. But in so far as we believe the wander- 

 ing cells and tbe branched cells they refer to to be identical, we agree 

 with them as to the parent-cells of the fat-cells. It is rather a 

 curious commentary on the term fixed branched cell of the connec- 

 tive tissue that Eanvier, one of the latest and best of histologists, 

 entirely denies the existence of such a cell, and endeavours to show 



