138 



THE DISSECTION OF PIG EMBRYOS 



in which the specimen may be kept indeflnitelv. Embryos may also be mounted in gelatin- 

 formalin solution in small sealed glass jars. 



Lateral Dissections of the Viscera. — Dissections like those shown in Figs. 144 and 

 145 may easily be prepared in less than an hour, and make valuable demonstration and 

 laboratory specimens. Sldll is required to demonstrate most of the cerebral nerves, but the 



Mesencephalon N. oculomotorius 



Cere 



Gang, genieulaliim ii 

 Go 



Giiu 

 Gang. 



Gang, jugulare u. 



Gang, petrosiim 

 N. hypoglossus 



N. accessorius 

 Gang, cerv 



Brachial ple.xus — TW 



milun. n. S 

 dihular ramus n. S 

 Ophthalmic ramus n. 5 

 N. opticus 



Cerebrum 



}[axillary ramus n. 5 



Chord.tymp. n. 7 



N. facialis 



Gang, nodos. n. 10 



R. atrium 

 R. ventricle 



Ventral lobe of liver 

 Umbilical cord 



Metancplir 



Nerve lo lower limb 



Sciatic nerve 



Fig. 144. — Lateral dissection of an 18 mm. pig embryo, showing the nervous system and viscera from 



the right side. X 8. 



central nervous system, cerebral and spinal ganglia, and viscera may easily be exposed. 

 Starting dorsally, make a sagittal section of the embryo slightly to one side of the median line 

 and avoiding the umbilical cord ventrally. With the embryo resting on the flat sectioned 

 surface, begin at the cervical flexure and with fine forceps grasp the ectoderm and dural anlage 

 at its cut edge, separate it from the neural tube and pia mater, and strip it off ventralwards 



