ON SUPllAREXAL BODIES IX THE MOUSE. 225 



the 14th day embryo, the blastemas have a considerable size, a little 

 projecting into the coelom cavity. The kidneys appear at the post- 

 erior and dorsal side of the suprarenaL By dissecting the embryo, the 

 suprarenals are seen as a pair of oval shaped bodies, flattened antero- 

 posteriorly as if pressed by tlie developing kidney. The inner end of 

 each su])rarenal is attenuated and thus overlaps the anterior inner 

 corner of each kidney, — a state of things retained and more distinctly 

 seen in later stages. In the 15th day embryo (woodcut 8), the 

 suprarenal bodies liave shifted their ])osition, farther dorsalward, 

 being now placed just laterally t(j the ^'ertebral body and dorsally to 

 the aorta. Thus at no stage, are the suprarenals of the two sides con- 

 nected together as some writers state. As Mitsukuri and Gottschau 

 well remarked, it is the ganglion placed inside of each suprarenal, 

 which is posteriorly joined to its fellow by a cross bar. 



The nerves sent out from the sympathetic ganglia are distinct in 

 the later stage of the loth day (woodcut 4). Two or three branches 

 are successively given out from the ganglia and all are united into 

 the splanchnic plexus lying inside of, and closely applied to, each 

 suprarenal. A Ijranch is further sent downwards from the plexus to 

 the front <jf the aorta, where it is connected (in the next day) with 

 its fellow of the other side. From the 14th day onward (woodcut 

 5), we can distinguish in each splanchnic plexus at least two 

 ganglia, the larger anterior and the smaller p(3sterior ones. The 

 posterior <j;ano^lion on the ri^'ht side is elono-ated and becomes con- 

 tinuous with the cieliac ganglion, no that the latter may be said to be 

 the direct continuation of the right splanchnic plexus. From the 

 ganglion closely applied to each suprarenal (that is the second 

 ganglion of the plexus), some fibres enter th(3 organ. Though very 

 fine, these fibres can be traced for a certain distance within the organ. 

 Woodcut () and tig. 9, taken from the 14t,h day embryo, repre- 



