230 M. IXABA. 



wns t'iie oldest one I investigated. The process takes place simply by 

 the growth of the connective tissue capsule around the piercing rierve 

 whicli is consequently reduced to a narrow neck and hnady cut ott' 

 (fig. 13). Still the direct connection of the niedulhi witli the 

 syni{>athetic ganglion is retained in some cases, especially on tlic left 

 side, fn all such cases observed, the connective link which persists 

 is enorinc^uslv strong, so much so that sometimes the ganglion itself 

 may be iimnersed in the organ. This is one reason why the 

 connection j)crsists longer. Fiu'ther ns before stated, on the left side 

 the nervous fibres entca- the organ mostly as a single conspicuous 

 bundle, whih^ on the right side they are usually divided into several 

 smaller clusters, which will more easily be cut off. Hence the 

 connection when it persists in tlie newly born mouse is always found 

 on the left suprarenal as before described. 



As to the general aj)pearance of the Idstological elements of the 

 suprarenal bodies in this stage, it does not much differ from those of 

 tlic newly born animal. 



Development of the Cortical Substance in the 11th- 

 1 :^ th day Embryos. — As regards the (n-igin of the cortical sul)stance 

 the attention of earlier writers has been principally directed to the in- 

 ditferent mesoblast. Kiilliker''' stated that the siipi-arenal bodies in the 

 rabbit first ap|)ear in the 12tli or 13th day embryo as masses of some- 

 what large round cells on each side of, and ventral to the aorta, on the 

 inner side of the Wolffian bodies and doi-sal to the mesentery. Mi- 

 tsukuri continued this and added that dors;dlv tliis mass is tolerably 

 distinct from the <)ther mesoblastic cells, but \entrallv its termination 

 is indetiiiite. Ihaimi', 13raun, and more i-ecentlv Gottschau derived 



f). Entwieklmio-sovscliiehte des Menschen uml der li('>lieren Thieve. 1S79. 

 7. Eiu Beitrage 7.nr Kentniss des feineren Baues und der Entwiclduno'sgeschichte der 

 Nebennieren. Arch. f. Mikros. Auat. VI IT. 1S72. 



