130 JEREMIAH S. FERGUSON 



Living connective tissue cells have been seen in tissue cultures 

 by Harrison, Burrows, Carrel and Burrows, Margaret R. and W. 

 H. Lewis and others, to exhibit a certain motility, and Harrison 

 has recently emphasized the stereotropic tendency of connective 

 tissue cells in cultures when in contact with foreign surfaces, 

 glass, spider-web, etc. But so far as I know, the histogenesis of 

 connective tissue fibers has not been so studied, and at best the 

 culture method is open to some criticism on the ground that while 

 the connective tissue cells are undoubtedly alive and active, yet 

 they exist under very unusual, if not abnormal, conditions whose 

 effects have not yet been subjected to complete analysis. Under 

 these conditions the behavior of the connective tissue elements 

 while probably similar, is not certainly in exact conformity with 

 that of the tissue within the embryo. 



In order that deductions based upon these several methods of 

 examination be adequately controlled it appeared desirable that 

 developing connective tissue be studied in the living animal under 

 conditions which were in every respect normal, or which, at least, 

 resulted in no inflammatory reaction. In mammals this endeavor 

 is fraught with considerable difficulty owing to the size of the 

 mammalian embryo and the depth beneath other tissues, often 

 not transparent, at which the connective tissue lies. 



During the past summer I had the opportunity, through the 

 courtesy of the Marine Biological Laboratory at Woods Hole, of 

 studying connective tissue in the fins of living fish embryos under 

 conditions which were wholly normal and unaccompanied by 

 any evidence of inflammatory reaction. 



If a free swimming Fundulus embryo is placed on a hollow 

 ground slide it will continue to swim, often actively, and its heart 

 beat and circulation are maintained. It may be observed for 

 some minutes and at the end of observation may be returned to 

 the aquarium to continue an uneventful existence for hours or 

 days thereafter. If a drop of chlorotone is added, or frequently 

 without its addition, the fish will remain quiet for some minutes, 

 thus permitting continued observation of connective tissue cells 

 in his semitransparent fins. Certainly cells studied under these 

 conditions are open to no criticism of abnormality. 



