8 C. W. M. Poyntcr 



a memoir in which he dealt with the other organs in addition to 

 the brain. The next elaborate work was that of ATarchand in 

 i889-'95, in which he analyzed the literature and discussed prin- 

 cipally the subject of etiology. Giacomini in 1890 carefully 

 reviewed the cases published up to that time, and introduced a 

 classification of defectives on the basis of pathology, separating 

 those cases which he termed microcephaly proper from cases of 

 obvious pathological causes. He was particularly fitted for this 

 work on account of his thorough knowledge of pathology, and, 

 as a result, little change has since been made in his classification. 

 Cunningham and Smith in 1895 made a study of a number of 

 microcephalic brains, analyzing them in detail and reaching con- 

 clusions in many respects confirming those of Vogt. 



The problem of etiology has been confused in the discussions of 

 many writers and made to mean, not the cause which produced a 

 being mentally inferior to the average of his race, but the condi- 

 tion of defectiveness itself; i. c, the operative factor or factors 

 are not distinguished from the condition of arrested development 

 or arrested development and retrodevelopment. Some of the 

 older authorities, as Jager (1839), considered that the condition 

 of microcephaly was produced by an arrest of development of 

 the skull (cause of arrest not suggested), which compressed the 

 brain and limited the growth. This idea w-as supported by the 

 opinion of Virchow as to the influence of the skull and brain- 

 growth on the early fusion of the sutures. Marchand (1895), on 

 the contrary, concluded that the small skull in microcephaly was 

 due to a lack of stimulus to growth through the pressure of the 

 enlarging brain. Some authors are of the opinion that the causa- 

 tive factor is active on the anlage while many believe it is opera- 

 tive at a much later period and quote the presence of certain 

 transitory fissures or of early normal fissures as a proof of their 

 contention. It can hardly be said that such evidence is satis- 

 factory. Sapolini (1870) was the first, I believe, to advance the 

 theory that the maldevelopment of the brain was the result of 

 faulty nutrition due to insufficient blood supply. He based the 

 theory on a very slender evidence. Two or three recent observers 



352 



