DR. BEALE_, ON THE TISSUES. 81 



fibres are many ganglion cells^ and here and there a micro- 

 scopic ganglion. 



The existence of small ganglia and ganglion cells in con- 

 nexion with the nerves of this and some other mucous mem- 

 branes is a point of great interest and importance, especially 

 when considered in connection with their absence beneath the 

 skin. Beneath the mucous membrane of the pharynx and 

 palate of the frog, ganglia and ganglion cells are present in 

 great number, but he has never seen one connected with the 

 cutaneous nerves. 



Oval nuclei or masses of germinal matter are very nume- 

 rous^ and are seen at very short intervals in all the nerve 

 fibres. They are most numerous in connexion with the finest 

 nerve fibres. They are also numerous on the vessels, as in 

 other parts. In a carelessly prepared specimen nothing but 

 these numerous nuclei, Avhich appear to be imbedded in a 

 slightly fibrous intermediate structure, are observed. Not a 

 nerve fibre is to be made out in some specimens prepared in 

 the ordinary manner, and were the density of the glycerine 

 in the specimens passed round altered a little_, the appear- 

 ance, now so distinct, Avould at once be lost. 



In some places, from carelessness in manipulation, the 

 distinctness of the nerve fibres is lost, and in these situations 

 the nuclei are seen in connexion with very fine fibres, not 

 altered by acetic acid, and resembling in all respects yellow 

 elastic tissue. In the external coats of arteries and in the 

 pericardium, similar appearances have been observed, and 

 from these and other facts, which will be alluded to in a 

 separate memoir. Dr. Beale thinks that certain forms of 

 yellow elastic tissue are the remains of nerve fibres, and 

 perhaps other structures which were in a state of activity at 

 an earlier period of life. 



Pericardium, its nerves and ganglia. — This was a specimen, 

 of the pericardium of the human foetus at the seventh month 

 removed from the surface of the heart. The capillaries have 

 been injected with Prussian blue. The bundles of nerve 

 fibres are seen crossing the field and dividing and subdividing 

 into smaller bundles, so that a network of nerve fibres with 

 wide meshes is formed. Numerous oval nuclei are observed 

 at short intervals in connexion with all the fibres forming 

 these bundles. The distribution of the finer branches cannot 

 be made out definitely because the fibres, except when a great 

 number are placed together, appear perfectly transparent. 

 Fibres of white and yellow fibrous tissue can be detected in 

 this specimen, but the quantity of connective tissue present, 

 is very small compared with that existing in the adult peri- 

 cardium. 



