i2r 



The researches of Arndt,^ however, claim special notice on 

 acconnt of their elaboration, the care with which he has col- 

 lated the opinions of many previous writers, and the remark- 

 able conclusions at which he arrives. My own observations, 

 although far more scanty than I could wish, having led me 

 to conclusions in some respects differing very materially from 

 those of Arndt, and in others equally from those of Lock- 

 hart Clarke,^ which unfortunately appear to have escaped 

 Arndt's notice, I venture to give a short account of what I 

 have seen, trusting that thereby at least others who enjoy 

 better opportunities of obtaining fresh specimens may be 

 aided in carrying the investigation further. 



My observations have been confined to the marginal con- 

 volution of the longitudinal fissure in the upper frontal and 

 upper occipital regions, and other convolutions in those 

 neighbourhoods. Extremely %veak chromic acid or bichro- 

 mate of potass I have, like Arndt, found to be the best pre- 

 servative fluids ; but, unlike him, I find that a great deal 

 can be made out even after preservation for more than a 

 fortnight, a little alcohol having been mixed with the fluid 

 to prevent mould. It is for the examination of the fibres 

 that the freshest specimens are necessary. Carmine-dyeing 

 is most useful in the examination of the nuclei, but the fibres 

 are not brought into view by it, the axis-cylinders in this 

 locality having no special attraction for the colouring matter, 

 and the ammonia being destructive of the medullary sheaths. 

 Turpentine lias failed with me as with others. Hile 1 have 

 fouud extremely iiseful in bringing the fibres into view. 



I have further to add that, whatever my success has been, 

 it has in great part been owing to the use of the " hold-fast 

 cutter" invented and patented by Mr. Stirling, of the Ana- 

 tomical Museum of the University of Edinburgh, an invalu- 

 able instrument, by means of which large and even secticms 

 may be made of the softest tissues. Happily Mr. Stirling 

 has been prevailed on to publish an account of this instru- 

 ment, which may be expected to appear iu ihe next number 

 of the ' Journal of Anatomy and Physiology.' 



The best basis for a nomenclature of the strata of the grey 

 matter of the convolutions still continues to be that of Kol- 

 liker, because, although imperfect, it is founded principally 

 on distinctions visible to the naked eye, which admit of no 



* Riidolpli Arndt in Scliultze's 'Arcliiv fiir Mikroskopisclie Anatomie,' vol. 

 ii, p. 441, vol. iv, p. 407, vol. v, p. 317. 



^ Lockhart Clarke, in ' Royal Siiciety's Proceed inQ:s,' vol. xii, p. 710 ; 

 and iu Maudsley's ' Physiology and Pathology of Miud,' Second Edition, 

 p. 60. 



