ANOMALIES OF THE ENCEPHALIC ARTERIES AMONG 



THE INSANE. 



A STUDY OF THE ARTERIES AT THE BASE OF THE ENCEPHA- 

 LON IN TWO HUNDRED AND TWENTY CONSECUTIVE CASES 

 OF MENTAL DISEASE, WITH SPECIAL REFERENCE TO ANOM- 

 ALIES OF THE CIRCLE OF WILLIS. 



BY 



I. W. BLACKBURN, M.D. 



Pathologist to Government Hospital for the Insane, Washington, D. C, Professor of Morhid Anatomy 



in the Medical Department Georgetown University, and in the Medical 



Department of the George Washington University. 



With Eleven Figures. 



Minor anomalies of the encephalic arteries are so common that 

 their study and observation have been mainly confined to modi- 

 fications of the circle of Willis and the principal basal trunks. 

 Slight deviation from the normal is very common in my autopsies 

 and probably in most cases unimportant, though it is claimed that 

 anomalies of the basal trunks are more common in the insane, to 

 quote Berkley, indicating some defect in the "molding of the 

 vital clay." Berkley admits, however, that comparative statis- 

 tics are vs^anting, while he states that in four cases out of sixteen 

 the arteries showed anomalies, a very large proportion. It would 

 seem evident that developmental defects in the arteries would in 

 most cases be compensated for by modifications of other trunks; 

 and that under normal conditions functions would be preserved, 

 but under diseased states and possibly unusual circulatory disturb- 

 ances the abnormality might be of serious importance. The actual 

 aetiological relationship of arterial anomalies to mental diseases 

 other than to defective developmental states, in which it may be 

 inferred, is hard to establish; but the relation they bear to gross 

 cerebral disease, and to surgical operations upon the cervical arteries 

 is easily demonstrated. 



It must be borne in mind in the study of these anomalies that 



