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J. J. MACKENZIE 



normal size, the shape was exactly that of a child of one year. There 

 was a full development of the medulla and an absence of fetal cortex. 

 More recently Meyer, Kern, Veit and Landau (a) have investigated the 

 condition carefully and have shown conclusively that the hypoplasia in 

 these cases did not involve the whole gland but only the cortex, that on 

 the other hand the medulla in these embryos was hyperplastic as compared 

 with embryos of the same age. Landau's explanation seems the most 

 plausible one. He points out that the physiological development oi 

 the human suprarenal may be divided into two stages; in the first 

 stage there is a general increase in size, that is during the first half 



of intra-uterine life ; in the sec- 

 ond half of intra-uterine life and 

 for some considerable time after 

 birth the general increase in size 

 gives place to an increase in sur- 

 face which results in the charac- 

 teristic folded shape of the fully 

 developed gland. As Elliott and 

 others have pointed out, the 

 most important change after 

 birth is the degeneration of the 

 inner cortical layers (fetal re- 

 ticulata and fasciculata) to 

 make room for the rapidly de- 

 veloping medulla, the cortex 



Fig. 1. Photograph of a section of the 

 right suprarenal of an anencephalous fetus of 

 about the eighth month. 



regenerating from the glomeru- 

 losa to form the permanent cor- 

 tex of the gland. Landau in his 

 studies on anencephaly has 



shown that the pathological changes in the gland seem to date from 

 about the sixth month of pregnancy. Meyer places the change at the 

 fifth month. Thus, in these cases the development of the suprarenals 

 pursues a normal course until about the mid-period of fetal life, when the 

 whole process takes on a more rapid tempo which parallels the changes 

 which occur in the normal infant after birth. The primary reticulata 

 and fasciculata degenerates rapidly, the medulla undergoes hyperplasia 

 arid at full term the fetus with extreme anencephaly shows a miniature 

 suprarenal with a medulla well developed, with complete disappearance 

 of fetal fasciculata and reticulata and with a thin cortex consisting of 



O 



glomerulosa arid newly formed fascicnlata corresponding in the propor- 

 tion of the various parts to that of an infant many months after birth. 

 In fact, the change which has been found may be regarded as a hurrying 

 forward of the changes during the second half of fetal life which normally 

 do not take place until after birth. The result is a gland which is only 



