390 Dr. A. W. Campbell. [Dec. 3, 



Addendum, January 19, 1905. The three rats inoculated on August 

 30, 1904, with extract of spinal cord have become paraplegic : one on 

 December 14, 1904, one on January 2, 1905, and the third on January 

 11, 1905. No Trypanosomata have been seen in the blood of these 

 animals, and, apart from paralysis of the hind limbs, they show no 

 signs of ill health. 



The spinal cord shows amoeboid forms of the Trypanosomata in its 

 tissue, and a considerable cellular exudation around the vessels ; this 

 lesion Dr. Mott found to be characteristic of cases of human Sleeping 

 Sickness, and it is not found in monkeys, which have been the animals 

 principally used in experimental work on this disease. 



* Further Histological Studies on the Localisation of Cerebral 

 Function. The Brains of Felis, Canis, and Sus compared 

 with that of Homo"* By ALFRED WALTER CAMPBELL, M.D. 

 Communicated by Professor SHERRINGTON, F.K.S. Eeceived 

 December 3, 1904, Eead January 19, 1905. 



(Abstract.) 



The present study is founded on an exhaustive examination of the 

 cerebral cortex of Felis domesticus, Canis familiaris, and Sus communis, 

 conducted on lines similar to those followed in the original work. 



A recurrence in the lower mammal of distinctive types of cortex, 

 akin to those recognised in the human brain, has allowed a subdivision 

 of the surface into the following areas : 



Crucial or motor; postcrucial or sensory; parietal; visual; ecto- 

 sylvian ; limbic ; rhinic ; extrarhinic ; frontal. 



By a study of the distribution of these areas many functional 

 analogies and structural homologies, previously unknown or mis- 

 interpreted, are made clear. 



Crucial or Motor Area. Giant cells of Betz characterise the motor 

 cortex, but these elements appear not to be so highly specialised in 

 Sus as in Felis and Canis. Such cells reside in what we may call the 

 cruciate zone, and it is maintained that this field is functionally and 

 morphologically akin to the motor area, as defined by Professors 

 Sherrington and Griinbaum in the anthropoid ape, and by myself in 

 man. It is held that a small indentation, called the " compensatory 

 ansate " sulcus, and the sulcus coronalis are respectively interchange- 

 able with the upper and lower constituents of the primate fissure of 

 Rolando, chiefly because they, like the fissure of Eolando, limit the 



* This paper is an addendum to the work presented to the Boyal Society in 

 November, 1903 (see 'Proceedings,' vol. 72, p. 488). The complete work will be 

 published shortly in full by the Cambridge University Press, by aid of a subsidy 

 from the Royal Society. 



