This is a work of great merit, in which the author compares the structure of the brain of man with that of other primates; he then treats of the morphology of the brain in different races, in criminals, in the insane, in deaf mutes, and in microcephales. An extremely interesting chapter is that devoted to the assumed difference of the cerebral hemispheres in the two sexes, containing statistical tables constructed by Dr. Mingazzini himself and others. Although he mentions certain minor differences that have been noticed by different observers, he summarises his own opinion by the statement that, "from the numerous but incomplete observations upon this subject, it may be concluded with certainty that essential differences do not exist" (si può inferire quasi con certezza che differenze essenziali non esistono). [19] Further information as to brain weight and cranial capacity, will be found in the author's treatise on "Aphasia and the Localisation of Articulate Language," chapter xii. (_Prize Essay of the Academy of Medicine of France._) [20] Op. cit., page 64. [21] The attention of the medical profession has lately been called to the obstetric aspect of idiocy, and I would refer those who take an interest in this subject to the valuable statistics of Dr. Langdon Down, which contain the result of his inquiries into the history of 2,000 cases of idiocy that have come under his observation; from which it would seem that primogeniture plays an important part, as no less than 24 per cent. of all the idiot children observed were primiparous. The increased difficulty of parturition seemed to be an important factor. In reference to the use of the forceps in delivery as an assigned cause of idiocy, Dr. Down says, "there is no evidence that instrumental interference has any injurious influence on the mental condition of the children, but he thinks that those who delay the use of the forceps incur a much greater risk from the prolongation of pressure, resulting in suspended animation, which condition should be especially avoided. Of Dr. Down's 2,000 cases, the ratio of males to females was 2·1 to 0·9. This was probably due to the larger size of the head giving rise to the prolonged and difficult parturition, continued pressure, and suspended animation."--_Obstetrical Journal_, vol. iv., p. 681.