210 



TWENTIETH LECTURE. 



Concerning the Pacinian capsules (Fig. 182) we have abun- 

 dant and no longer to be doubted material. 



These structures have had a 

 peculiar history. 



They have been known for 

 more than one hundred and thirty 

 years. 



They were described in 1741, 

 in the doctor's dissertation of a 

 certain Lehmann, having already 

 been discovered by a professor 

 Vater of that period. They were 

 forgotten for nearly three genera- 

 tions. 



They were rediscovered soon 

 after 1 830, without any presenti- 

 ment of a predecessor, by Pacini 

 of Pistoja and, almost simultane- 

 ously, on the occasion of an ana- 

 tomical concourse, by Parisian 

 physicians. The attention of 

 the German investigators was 

 especially directed to our structure by the monographs of 

 Henle and Koelliker, in the year 1844. As a student at 

 that time in Gcettingen, I had already found them in the 

 abdominal cavity of the cat, and had seen the entering 

 nerve. 



Let us leave these historical reminiscenes, however, and 

 pass to matters of fact. 



The Pacinian bodies appear as elliptic structures, measur- 

 ing 1 to 2 mm. and more, sometimes more elongated, some- 

 times more developed in width. Without the microscope, 

 we perceive them to be tense, tolerably firm, semi-transpar- 

 ent, and with white axial striations. 



They are regularly met with in the human body on the 

 nerves of the palm of the hand and the sole of the foot, 

 especially of the fingers and toes. Their total number varies 



FlG. 182. — Pacinian body from the mes- 

 entery of the cat ; a, nerve fibre with its 

 envelope, forming the stem ; b, the cap- 

 sular system ; c, the axis canal or inner 

 bulb, in which the nerve tube ends. 



