Congenital Anomalies of Arteries and Veins 29 



ported as a branch of the coehac artery. These observations agree 

 quite closely with those of Levi (1909), who studied 96 bodies. 



A. Renalis 



Bremer (191 5) made a study of the development of the renal 

 circulation and found an early preaortic plexus from which he con- 

 cluded that the renal arteries are derived through mechanically 

 selected channels. He applied this idea to the explanation of the 

 anomalies which are so frequent. He opposed the idea of the de- 

 velopment of late branches. Both renal arteries may spring from 

 a common stem, Portal (1803), Dubrueil (1847). 



The most frequent anomaly is an increase in the number of 

 arteries to the kidney. These variations have long been recog- 

 nized. Murray (1798) said : " The anatomists said that there was 

 such a variety both in number and position of this artery as to 

 make it without profit to enumerate them." 



The number of arteries varies from two to six, the most fre- 

 quent being two. An accessory artery to the lower pole is more 

 frequent than to the upper ; not infrequently two small arteries to 

 the hilus take the place of the normal single vessel or the artery 

 may be double for a short distance. Usually the accessory artery 

 springs from the aorta, but may have an origin from various other 

 sources, as: suprarenal, Gerard (1913), Poynter; coeliac artery, 

 Macalister (1883), Gillepsie (1916) ; superior mesenteric, Kolster 

 (1902). Gillespie (1916), Poynter; inferior mesenteric, Cavasse 

 (1856), Macalister (1883) ; the common iliac, Ouain (1844), Bar- 

 kow (1851), Pilate (1867), Glason (1868), Hyrtl (1868), Dufour 

 (1852), bavies-Colley (1873). Macahster (1883), Tuffier (1886), 

 Brodie (1893), Hepburn (1891), Thomson (1890), Mahon 

 (1889), Tonkofif (1903), Young (1903), Kater (1901), Roussy 

 (1904), Bouteil (1909), Harvey (.1914), Poynter; from the mid- 

 dle sacral. Bonnet (1835), Otto (1830), Hyrtl (1841), Barkow 

 (1851), Struthers (1892), Macahster (1883), Londe (1890), 

 Harding (1898). Brodie (1893), Poynter; from the external iliac, 

 Macalister (1883), Tonkoff (1903)- 



From study of the literature I find no difference in frequency 

 between the two sides, and the number of bilateral conditions con- 



