120 MANUAL OP HISTOLOGY. 



process and the superficial or spiral fibre, which corresponds to 

 the branched fibre of the ganglionic bodies of the brain and 

 spinal nerves. 



Ganglia of the cranial and spinal nerves. These organs, 

 which appear to the naked eye as nodular enlargements of the 

 nerves with which they are connected, consist of groups of 

 peculiar large corpuscles which are interspersed among the 

 nerve-fibres. In shape they are usually large and ovoid, or 

 pear-shaped. About and between them are bands of connective 

 tissue studded with nuclei, forming for each separate body a 

 kind of capsule ; the vascular supply to them is liberal. The 

 contents of these bodies are soft, elastic, and beset with gran- 

 ules. They have a large, globular, or ovoid nucleus or nucleo- 

 lus, and may appear to have no process, or to be unipolar or 

 bipolar, as in the lower animals. 1 



Examination of the Gasserian ganglion in the frog. 

 Take a frog that has just been killed, or, better still, one that 

 has been some time in Mueller' s fluid ; trace the fifth nerve 

 into the skull. On it will be seen, just within the bone, a yel- 

 low enlargement. This is to be removed with forceps and 

 teased with needles. The ganglionic bodies usually appear to 

 have no processes (apolar), but they probably have one or more, 

 and the apparent absence of them is because they have been 

 torn off in teasing. 



Examinatio7i of the ganglia of the spinal cord. Take the 

 cord of a bullock, and prepare it while fresh, or after it has 

 been a greater or less time in Mueller' s fluid, or a weak so- 

 lution of the bichromate of potash (gr. xv. j.). Having cut 

 it into transverse segments, the gray substance may be easily 

 seen. Snip out with fine curved scissors small pieces from the 

 anterior horns in the lumbar regions where the corpuscles are 

 very numerous ; if the specimen be fresh, immerse in osmic 

 acid (11,000) for twenty -four hours. Then, by careful brush- 

 ing in water with the camel' s-hair brush, or by teasing, or agi- 

 tation in a test-tube with a little distilled water, some of the 

 ganglkmic corpuscles will be successfully removed. They will 

 be seen to vaTv^ much in size, and be multipolar, i.e., they will 

 exhibit a very lafge number of branches (Deiter 's protoplasmic 

 -^ ^^ 



1 According to Key and RetHj 1 ^ they are probably all unipolar. Stud, in der 

 Anat. d. Nerven-Syst., 2 Halfte, vS*""! H.'s Jahresb., 1878. 



