A STUDY OF THE REACTION OF LYMPHATIC ENDO- 

 THELIUM AND OF LEUCOCYTES, IN THE TAD- 

 POLE'S TAIL, TOWARD INJECTED FAT 



ELIOT R. CLARK AND ELEANOR LINTON CLARK 



From the Anatomical Laboratory of the University of Missouri 



NINE FIGURES 



INTRODUCTION 



The present investigation is part of a series undertaken in 

 order to study the growth and reactive powers of Uving tissues 

 and cells in the tadpole's tail. These experiments were planned 

 particularly in order to find out whether lymphatics react, by 

 growth processes, to the stimulus of specific external substances, 

 with the ultimate object of determining, if possible, what regu- 

 lates the growth of lymphatic endothelium. Such a study in- 

 volves observations on other tissues, such as blood vessel endo- 

 thelium, mesenchyme cells, and leucocytes. » 



The transparent tail of the frog larva is admirably adapted to 

 the experimental investigation of the growth and reaction of 

 these types of cells and tissues because of the readiness with 

 which this animal lends itself to experiment and to observation 

 under chloretone anaesthesia, because of the ease of watching 

 the behavior of each cell, in the living animal, and also because 

 the normal mode of growth of the tissues present in the tad- 

 pole's tail has been thoroughly established. 



One of the authors (3, 4), in extensive studies in which every 

 capillary and mesenchyme cell, for certain regions of the same 

 tadpole, were carefully watched and recorded, for periods of 

 several weeks, has shown that, at the stage when the tail has 

 become transparent, connective tissue cells, wandering cells, 

 blood vessels, and lymphatic endothelium are each specific and 



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THE AMERICAN JOURNAL OK ANATOMY, VOL. 21, NO. 3 



