FURTHER OBSERVATIONS ON LIVING GROWING 



LYMPHATICS: THEIR RELATION TO THE 



MESENCHYME CELLS 



ELIOT R. CLARK 

 From the Anatomical Department of The Johns Hopkins University 



EIGHTEEN FIGURES 



In an earlier paper/ read before the American Association of 

 Anatomists in December 1908, the results were given of a series 

 of observations on the "method of growth of lymphatic capillaries 

 as revealed by a study of the transparent fin expansion of the tail 

 of living frog larvae. The present paper of which the essential 

 parts were presented to the American Association of Anatomists 

 in December 1910, represents the results of a newer set of studies, 

 made during the spring of 1910. 



The methods employed in the second study were identical 

 with those used in the first; they deserve a fuller description than 

 has been given. As there stated, two factors are essential to 

 the success of the observations, an upright chamber and chlore- 

 tone anesthesia. The former allows the larva to remain in its 

 normal upright position while being watched; the latter keeps 

 it motionless, without seriously interfering with the circulation 

 of the blood or with the growth of the tissues. 



The upright chamber which was used is by no means new to 

 the histological laboratory. The earliest description of such an 

 apparatus which I have found is by Cori. 2 In the article in 

 Zeitschrift fur wissenschaftliche Mikroskopie he describes the first 

 apparatus, which he devised, as follows: 



1 E. R. Clark, Observations on living, growing lymphatics in the tail of the 

 frog larva. Anatomical Record, vol. 3, no. 4, 1909. 



2 Cori, Lotos, Bd. 13, referred to in Zeitschrift fur wissenschaftliche Mikros- 

 kopie, Bd. 10, 1893, p. 149. 



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