1864.] Mr. A. J. Ellis on a Perfect Musical Scale. 



93 



that was seen. There was a proper canal for the spinal cord, but it had no 

 osseous covering. The deep groove bifurcated at the cranial extremity into 

 grooves of half its size, which took a direction at right angles to that of the 

 former. The left pneumogastric nerve was seen passing through the base 

 of the cranium to the surface, where it appeared to have come from the 

 membrane from which other nerves proceeded. After descending to the 

 cervical region and giving off the recurrent, the principal branch was not 

 continued to the lungs and oesophagus, but directly to the ganglion of the 

 sympathetic in the upper part of the thorax, so that the sympathetic 

 chain of ganglia in the thorax appeared to be simply a continuation of the 

 pneumogastric. To compensate for this absence of nervous supply on the 

 left side, the nervous plexuses on the roots of the lungs were found to be 

 enormously increased on the opposite side. A large branch ascended from 

 the solar plexus and united with the divisions of the right pneumogastric. 

 The splanchnic on this side was large, and was composed of filaments 

 from the upper thoracic ganglia, not merely from those below the sixth. 

 The action of the heart and the functions of the liver, kidneys, and other 

 organs must have continued during the uterine existence of the foetus. 



The author expects to be afforded further means of prosecuting his 

 dissections of the nerves of acephalous monsters, in which case he will 

 communicate the results of his examinations to the Royal Society. 



II. " On the Conditions, Extent, and Eealization of a Perfect Musical 

 Scale on Instruments with Fixed Tones.^^ By Alexander J. 

 Ellis, B.A., F.C.P.S. Communicated by C. Wheatstone, Esq., 

 F.R.S. Received January 7, 1864. 



EuLER*, perceiving that the relative pitches of all musical notes might be 

 represented by 2"" . 3" . 5^, formed different " genera musica " by allowing 

 n SLudp to vary from to fixed limits. His ''genus diatonicum hodier- 

 num" (op. cit. p. 135) limits n to 3 and^ to 2, and consists of 12 tones. 

 These tones and 12 others are contained in his "genus cujus exponens est 

 2™ . 3^ . 5^" that is, which limits n to 7 and p to 2. He has further {ib. 

 p. 161) given a scheme in which each manual of an instrument should 

 represent two sounds, the primary belonging to the first 12 tones, and the 

 secondary to the additional 12. He says p. 162), *'Soni secundarii 

 summo rigore ab iisdem clavibus edi nequeunt, quia vero tam parum a 

 primariis discrepant, ad eos exprimendos hae claves sine sensibili har- 

 monicB jactura tuto adhiberi possunt. Nam etiamsi ab acutioribus auri- 

 bus comma seu diaschisma, quibus intervallis soni secundarii a primariis 

 differunt, distingui queaty tamen quia soni secundarii cum primariis neque 



* Tentamen Novae Theoriae Musicse ex certissimis Harmonige principiis di- 

 lucide expositee auctore Leonhardo Eulero. Petropoli, 1739. 



