On a system of fibre-cells 



surrounding the blood-vessels of the Brain of Man and 



Mammals, and its Physiological Significance 



by 



Dr. W, Lloyd Andriezen, 



(From the Pathological Laboratory of the West Riding Asylum, Wakefleld, England). 



(With pi. XXI.) 



My object in the present communication is to make known a 

 series of new observations in regard to a liitlierto-unrecognized peri- 

 vascular system of //'ore-cells which form a definite sheath-like structure 

 in the Human Brain, and to demonstrate the importance and signi- 

 ficance of this sheath. 



The investigations are based mainly on the Human Brain, of 

 Avhich nearly 40 specimens have been systematically studied, while as 

 a control and aid to the investigation the brain of kittens (newboi'n 

 and young) have been utilized, especially to trace the growth and 

 developement of this perivascular structure. 



Studies have also been made with concordant results on the 

 Brain of the adult cat, rat, rabbit, and ox. The Human Brains were 

 from Post-Mortems of an average of 24 lirs. old, a few being less 

 than 12 hrs. 



The appearances described below mainly for the Human Brain 

 are frequent and constant, and in successful preparations can leave no 

 possibility of doubt, while the occurrence of the same structures in the 

 brains of the kitten and other animals above mentioned indicate that 

 the structure in question is a normal and physiological one. 



