Franklin P. Mall 



337 



the arrangement of the bundles of exoplasm into an extremely dense 

 network. In the tail the endoplasm around the nucleus forms a stellate 

 mass with fibrils from the points running over into the fibrillar exo- 

 ])lasm of the main bod}- of the syncytium (Fig. (3). Within the exoplasm 

 there are some fibrils more sliarply defined than the rest, which often 

 appear to be composed of rows of extremely minute granules. 



When the connective-tissue syncytium is fully developed in the tad- 

 pole it shows practically all of the characteristics found in mammalian 

 embryos. I have made numerous chemical tests with the syncytium in 

 the embryo pig, as an abundance of this material is constantly at my 

 disposal. The tests were made with various stains, and dio-estive fer- 



■'c?>; 



■':^:^ 



*:cm 



-«B-- 









Fig. 5. 



Fig. 6. 



Fig. 5. Connective-tissue syncytium just below the ectoderm in tbe anterior part 

 of tlie head of a tadpole 9 mm. long ( x 500 diameters.) 



Fig. 6. From the tail of the tadpole from which Fig. 5 was drawn. 



ments npon sections which had been cut in paraffin. Frozen sections 

 were also used a great deal, with more or less satisfactory results, to 

 control the above, and to test with acetic acid, caustic potach, pan- 

 creatin, and pepsin. 



The Coxxective-Tissue Syxcytium ix the Pig. 



The connective-tissue syncytium is fully developed in the embryo 

 ■pig from 9 to 12 mm. long. At this time it corresponds wdth that of 

 the tadpole 6 mm. long. In the greater portion of the embryo, how- 

 ever, the syncytium is pretty well obscured by its numerous nuclei with 

 the exception of that in the skin, around the brain and on the dorsal 



