CHAP, n] (General Remark* <t Cortical Fibre antf Cell Arratif/enii'iif 7 



a modification i it Wei Bert's original hematoxylin process a method which he adhered to 

 faithfully throughout his researches and which I also have adopted. In his second paper 

 he gives details of an exhaustive examination of the brains of two males, aged 18 and 38 

 respectively, and supplies an excellent account of the developmental differences which are to 

 he met with in the cortex at these two periods of life. An analysis of sections of no less 

 than seven brains forms the basis of his third paper, and in it the appearances presented 

 liy the brain of an infant aged one and a c|iiarter years are compared with those in adoles- 

 cence, the prime of life, and old age. In his final paper, he discusses the cortical nerve fibres 

 in the brains of two idiots. Ka.es' method of procedure was an extremely thorough one. 

 The hemisphere for examination was first sliced vertically into 12 blocks of equal thickness; 

 each block was then cut seriatim on a large microtome, so that eventually a series of com- 

 plete coronal sections 1 of the hemisphere was obtained, displaying the structure of the cortex 

 in every part. The measure of praise which Kaes' labours deserve may be gauged from the 

 tact that he devoted one and a half years' incessant toil to the preparation of sections of 

 each hemisphere examined, but for this, the honour of being the first to have made a survey 

 of the medullated fibres over the whole cerebral surface is some recompense. The expense of 

 reproduction has unfortunately prevented him from publishing the series of drawings, which 

 he has prepared for exhibition at meetings of various German Neurological Societies, and his 

 papers are only illustrated by a few freehand sketches, and some diagrams, in which he 

 attempts to show by means of coloured lines the degree of development of the medullated 

 nerve fibres and their richness of representation in the various layers, etc., throughout the 

 cortex. These diagrams only serve their purpose in a rough manner, for the investigator 

 desirous either of checking the results or of prosecuting further research will find them 

 wanting in precise points of orientation ; points which must be so carefully observed in work 

 of this nature, and which an outline drawing of the hemisphere, giving the exact relation of 

 the different types of structure to the fissures, would better afford. The second and most 

 serious criticism which I have to offer is that the lines on which the work has been conducted 

 have been too narrow ; in particular, neglect of the underlying principle, that differences in 

 physiological function are probably correlated with variations in structure, detracts from its 

 value in the eyes of those interested in localisation. 



S. Ramon y Cajal's recent publications must next be referred to. I understand that the 

 great Spanish histologist has determined to carry his investigations over the entire cortex, 

 but hitherto the German translations of his works on the cortex of the visual, motor, auditory 

 and olfactory areas, respectively, published for the benefit of those who, like myself, are not 

 familiar with Spanish, have alone appeared. But these papers in themselves are of immense 

 value, for with his unequalled knowledge of histological technique as applied to the nervous 

 system, he has made free use of the principles involved in the method of Golgi, Nissl, and 

 Weigert, and has been enabled to give a clearer account of the composition of the cerebral 

 cortex, and a more satisfactory explanation of the physiological significance of the contained 

 nervous elements, than any other writer on the subject. His papers are profusely illustrated, 

 chiefly with drawings from Golgi preparations, and all four are models of scientific thorough- 

 ness. When Ramon y Cajal published his work on the motor area, Sherrington and Griinbaum's 

 investigations were not made known, hence he has included the post-central convolution in 



1 Latterly he found it more advantageous to cut the central convolutions in a sagittal direction, i.e. at right 

 angles to the fissure of Rolando. 



