217 



that the sulcus lunatus may be regarded as a normal feature of the 

 adult human brain. 



This conclusion is in direct conflict with the statements of Bi- 

 SCHOFF^), Cunningham-), and others to the effect that the "Aifen- 

 spalte" is represented in the human foetal brain by a furrow (B.'s 

 "Fiss. perpendicularis ext."), which makes its appeai-ance in the 5th 

 month (according to C.) and disappears in the 7th month. The question 

 naturally presents itself: what is the nature of this "fiss. perpend, ex- 

 terna" ? 



Two kinds of so-called "transitory fissures" have been described 

 in the foetal human brain. There is the group of irregular puckerings 

 of the neopallium, which are found in those foetuses of the 3rd and 

 4th months in which putrefactive changes have begun : and there is a 

 second group which are found in foetuses of the 5th, 6th and 7th 

 months. It is quite unnecessary to discuss the first group, because 

 their true nature as post-mortem wrinklings of the neopallium has 

 been conclusively demonstrated by Hochstetter ^) , and the results 

 of the examination of all the known fresh foetuses of the 3rd and 

 4th months amply confirm the results obtained by H.'s researches^). 



Cunningham is, so far as I am aware, the only writer who spe- 

 cifically states that H.'s arguments "do not explain all the circum- 

 stances of the case" (Text-book of Anatomy, Edinburgh, 1902, p. 555), 

 [Wilder, it is true, still clings to the old teaching in his recent work 

 (Article "Brain" in the Reference Handbook of the Medical Sciences, 

 1902, p. 186); but he appears to be ignorant of the important work 

 of HocHSTETTER and Gustaf Retzius.] C. beheves that the surface 

 of the neopallium is much too extensive during the 3rd and 4th 

 months of foetal life to be packed without such "transitory foldings" 

 in the limited space afforded by the cranial cavity: therefore, he ar- 

 gues, the "transitory fissures" must be genuine features of the living 

 brain at that time. This argument, however, ignores the undoubted 



au der Wiener Universität (herausg. v. Prof. Dr. H. Obebsteinbr), 1902, 

 Heft 9, p. 118 sq. 



1) BiscHOFF, Abhandl. d. K. Akad. d. Wissensch., II. KL, Bd. 10, 

 p. 448. 



2) Cunningham, Memoirs of Royal Irish Acad., 1902, No. 7, p. G6 — 71. 



3) HoCHSTETTBR, Bibliotheca niedica, Abt. A, Anatomie, herausg. von 

 Prof. Dr. G. Born, Stuttgart 1898. 



4) Gustaf Retzius, Anat. Anzeiger, Ergänzungsheft zum 19. Bd., 

 1901. — Idem, Biolog. Untersuchungen, Neue Folge, X, Stockholm 1902. 

 — K. Goldstein, Anat. Anzeiger, Bd, 22, No. 19, Jan. 1901. — Franklin 

 P. Mall, American Journal of Anat., Vol. 2, No. .3, July 1903, p. 833 sq. 



