Royal Society. 65 



series will famish the numbers requisite to carry on the notation by 

 the new and more numerous combinations which must of necessity 

 be of the same numerical kind with those which have preceded them. 

 It is shown at length, that the new combinations, as the series ad- 

 vances, do actually increase in an increasing proportion compared 

 with the numbers required. 



2. " Experiments on the section of the Glossopharyngeal and 

 Hypoglossal Nerves of the Frog, and Observations of the altera- 

 tions produced thereby in the Structure of their primitive fibres." 

 By Augustus Waller, M.D. Communicated by Professor Owen, 

 F.R.S. &c. 



After describing the natural structure of the tubular fibres of the 

 nerves, the author states the results which he observed to follow 

 the section of the nerves of the frog's tongue. To this organ two 

 principal pairs of nerves are distributed ; one of these, issuing from 

 the cranium along with the pneumogastric and distributed to the 

 fungiform papillae, is regarded as the glossopharyngeal ; the other, 

 arising from the anterior part of the spinal cord, and passing through 

 the first intervertebral foramen, the author (following Burdach) 

 names the hypoglossal. Section of the glossopharyngeal nerves 

 does not cause any perceptible loss of motion or of common sensa- 

 tion, and this fact, together with its distribution to the fungiform 

 papillae, leads the author to consider this nerve as the nerve of 

 tasting. On the other hand, when the hypoglossal nerves are 

 divided, the tongue is no longer sensible to mechanical irritation, 

 and its motions are entirely abolished. Simultaneous division of 

 the right and left glossopharyngeal nerves is followed by the death 

 of the animal in a few days, and the same effect ensues after division 

 of both hypoglossals. This result, which takes place more speedily 

 in summer than in winter, the author is disposed to ascribe to a 

 disturbance of the mechanical process of respiration, in which, as is 

 well known, the muscles of the frog's mouth and tongue take a 

 large share. 



To ascertain the changes which take place in the nerve-fibres 

 after division of the trunks to which they belong, the operation was 

 confined to the nerve of one side only, and the fibres of the unin- 

 jured nerve of the other side served for comparison. These changes 

 ensue more speedily, and go on more rapidly in summer than in 

 winter, commencing usually in about five days. The pulp contained 

 in the tubular nerve-fibres, originally transparent, becomes turbid, 

 as if it underwent a sort of coagulation, and is soon converted into 

 very fine granules, partly aggregated into small clumps, and partly 

 scattered within the tubular membrane. These granules are at first 

 abundant, and render the nerve-fibre remarkably opaque ; but in pro- 

 cess of time they diminish in number, and, together with the inclosing 

 membrane, at length disappear, so that at last the finest ramifications 

 of the nerves which go to the papillae, or those going to the muscular 

 fibres of the tongue (according to the nerve operated on), are 

 altogether lost to view, in consequence of the destruction and eva- 



PML Mag. S. 3. Vol. 37. No. 247. July 1850. F 



