THE HUMAN PROSTATE GLAND 301 



Gustaf Pallin 7 summarizes the results of his study of human 

 embryos aged three and four months by means of wax models as 

 follows : 



The prostate gland is deposited in male embryos in the third month 

 by separation of the solid longitudinal folds on the outer side of the epi- 

 thelial wall of the urethra. Three groups of prostatic tissue are dis- 

 tinguished, (1) Cranialwards from the genital cords lying dorsally, (2) 

 Caudalwards from the genital cords lying dorsally,. (3) Ventral. 



Both of the first groups go out from the prostatic furrows. From the 

 cranial the main mass of the base of the prostate will be composed; the 

 third lobe seems not to be composed of independent glands but ramifi- 

 cations of the cranial glands can grow into the midline and then these 

 become gland parts. The caudal dorsal structure forms the lateral and 

 hind part of the side lobes. The ventral group at first occupies the 

 greater part of the forward urethral wall. The number of its glands 

 becomes reduced in the fourth month and it appears then in the midline 

 as a forward lobe. In certain cases the reduction of this lobe amounts 

 to complete atrophy. 



This article is very extensively quoted and accompanied as it 

 is by drawings from wax models and very accurate descriptions 

 has influenced many workers. 



Jores 8 states that the middle lobe can be considered only as a 

 glandular commissure connecting the two lateral lobes and not as 

 an independent structure. 



The posterior lobe is generally referred to in the literature as 

 originating from ingrowths from the lateral lobes. 



The number of tubules of the various parts of the prostate 

 emptying their secretions into the prostatic urethra is usually 

 stated in text-books to be between twenty and thirty, while the 

 proportion of glandular tissue compared to the interglandular 

 stroma is quoted by different authors to be from one-third or one- 

 half (Kasuyoshi Nakasima) to five-sixths (Walker). The later 

 writers seem to be agreed that the prostate begins to develop at 

 about the third month of intra-uterine life. Kolliker thought 

 that it was not present until the fourth month and Mihalkovics 

 placed the fifth month as its beginning. The smooth muscle of 

 the gland, according to the latter and also Tourneux, began to 



7 Gustaf Pallin, Archiv fur Anatomie und Physiologie, 1901. 



8 Jores, Virchow's Archiv fur pathologische Anatomie, Bd. 135, 1894, p. 224. 



