402 OTTO F. KAMPMEIER 



In 1909 Sabin 2 published a paper on the origin of the lymphatic 

 system in the pig which reinforced and extended the theory of 

 Langer 3 and Ranvier, 4 that lymphatic vessels arise from the veins 

 by a process of sprouting and centrifugal growth. Because her 

 results and conclusions did not present fully all of the evidence or 

 agree with the results of later investigations, Professor McClure 

 suggested to the writer the expediency of repeating her work on 

 the same kind of material, namely, pig embryos, but restricting 

 this research to one lymphatic channel and concentrating upon 

 it alone all attention. The thoiacic duct was selected on account 

 of its size, importance, and definite position in the body, thus 

 serving better as a test or control than perhaps any other lymph 

 channel. 



For the completion of this work, carried on during the last two 

 years, I am indebted to Professor McClure for his advice and 

 valuable criticisms, and to Dr. A. G. Brown of Columbia Univer- 

 sity and to Mr. Charles F. Silvester for their hints in the prepara- 

 tion of the microphotographs. I acknowledge my gratitude to 

 Professor Houser for permitting me to use the laboratory at 

 the Iowa State University during the summer of 1910. My 

 thanks are also due to Professor Sabin for the use of series 23a 

 of the Johns Hopkins University Embryological Collection, and 

 for the privilege of publishing any information or evidence which 

 might be derived from this series. 



II. MATERIAL AND TECHNIC 



Most of the embryos used in this work were fixed in Zenker's 

 fluid and the sections stained on the slide with Delafield's haema- 

 toxylin and orange-G. Sabin's, series 23a was preserved in the 

 same fixative but stained with Congo red. A few embryos were 



2 Florence R. Sabin : On the origin of the lymphatic system from the veins, and 

 the development "of the lymph hearts and thoracic duct in the pig. Am. Jour. 

 Anat., vol. 1, 1902, pp. 367-389. 



3 C. Langer: Ueber das Lymphgefass-systems des Frosches. Sitzb. d. Akad. d. 

 Wissensch., Bd., 57, 1, Abth., 1868. 



4 L. Ranvier : Morphologie et developpement des vaissaux lymphatiques chez 

 les mammiferes. Comptes Rendus, 1895, 1896. Archives d'Anatomie Micro- 

 scopique, tome 1, 1897. 



