186 
ON THE SYMPATHETIC NERVOUS SYSTEM IN MAMMALS. 
PLATE 26. 
Fig. II. Sagittal section of Rat embryo (about 8 days). Sy., sympathetic cord; Mo., 
mouth; To., tongue ; TTy., hypoglossal nerve; R. IE., body-wall; iT, heart; 
Per.C., pericardial cavity ; L., lung ; Pl.C., pleural cavity ; Art., carotid artery ; 
V., vein ; Va., vagus ; V.S., vertebral somites ; D.G., dorsal ganglia ; Br., 
brain. 
Fig. 12. Sagittal section of Rat embryo (about 10 days). 
Fig. 13. Transverse section of sympathetic cord {Sy.) in Rat embryo (about 14 days) 
in thoracic region. Ao., aorta; Spl., splanchnic branch of nerve, dividing into 
(a) a branch joining the cord, and (;8) a branch passing beyond it—y, a cellular 
branch arising from the cord, and accompanying (/8). 
PLATE 27. 
Fig. 14. Sagittal section of Rat embryo (about 15 days), showing the anterior termi¬ 
nation of the sympathetic {Sy.). Sp.C., spinal cord; Bust., Eustachian tube. 
Fig. 14a. Sagittal section of same embryo (15 days), showing posterior termination 
of sympathetic {Sy.). Sr.C., suprarenal body; K., kidney; Sto., stomach. 
PLATE 28. 
Fig. 15. Sagittal section of Mouse embryo (about 17-18 days). E.R., vertebral somites 
(cartilaginous) ; hit., intercostal vessels {Cf. fig. 10). 
Fig. 16. Transverse section of Human embryo, aged about one month, in thoracic 
I’egion. 
PLATE 29. 
Fig. 17. Sagittal section of Mouse embryo (about 17-18 days), showing anterior 
termination of superior cervical ganglion {Sy.). Art., internal carotid artery. 
Fig. 18. Sagittal section of Rat embryo (about 22 days) in lower thoracic and lumbar 
regions. Aw., lung; Ro, diaphragm ; Ah, liver; P/. C., pleural cavity ; Perit.C., 
peritoneal cavity ; S.G., semilunar ganglion ; Sol., solar plexus ; Sy., sympa¬ 
thetic cord. 
PLATE 30. 
Fig. 19. Sagittal section of Human embryo, about f inch long. Sy., sympathetic 
cord, joined by splanchnic branches {Spl.). 
Fig. 20. Transverse section through sympathetic cords {Sy.), middle sacral artery 
M.S.A.), and veins ( V. V.), with peripheral branches {Br., Br.), and a connecting 
commissure {Co.). Rat embryo (about 22 days). 
Fig. 21. The sympathetic cord, from dissections of Human embryos in the {A.) third, 
(P.) fourth, [C.) fifth, and {D.) sixth month. S.G., M.G., I.G., superior, middle, 
and inferior cervical ganglia; C.P., V.P., carotid and veitebral plexuses; 
G.Spl., great splanchnic nerve, with ganglion (Ah). Connexions with various 
spinal nerves, numbered in order: C., cervical, 1, 2, 3, 4, &c. ; D., thoracic; 
A., lumbar; S., sacral. 
