ON THE FATE OF THE JUGULAR LYMPH SACS AND 

 THE DEVELOPMENT OF THE LYMPH CHAN- 

 NELS IN THE NECK OF THE PIG 



ADMONT H. CLARK 



From the Anatomical Laboratory, Johns Hopkins University 



FOUR FIGURES 



In a study of the morphological changes which the jugular 

 lymph sacs and the lymph channels in the neck of the embryo 

 pig undergo during development, a number of questions must be 

 considered. \\Qiat are the primary lymph channels? Are they 

 characteristic and constant in form? How are they modified 

 during development? What is the correlation between the 

 earliest lines of drainage and the drainage found in the adult? 

 What are some of the factors controlling these transformations? 

 These and other questions arise. The purpose of the following 

 paper is to make an analysis, and to offer a few suggestion 6n the 

 points mentioned above. '' 



The undertaking of this work was suggested by-Dr. Sabin, and 

 it was through her kindness that this stu^y' was possible. There 

 have been accumulating in the lab,9rat6ry from previous studies a 

 number of injections of lymp^*a.tics in embryo pigs of all stages 

 made by Dr. Sabin. These with numerous new injections have 

 been cleared by the Spalteholz method,'^ and the present paper is 

 based on a comparative analysis of these specimens. It has 

 been the aim to give as accurately as possible the location of the 

 lymphatics and the morphological changes in successive stages of 

 development. There has been no attempt to describe the minute' 

 structure of the lymphatics but simply to trace the gross changes 

 in the lymph channels. 



1 Spalteholz, W., Ueber das Durchsichtigmachen von menschlichen und tieri- 

 schen Praparaten. Leipzig. Verlaz von S. Hirzel. 1911. 



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