62 HUBER. [Vol. XVI. 



Ramon y Cajal's studies on the sympathetic system were pub- 

 lished in three papers, which followed each other in close succes- 

 sion. In his second communication, to which I wish here to 

 refer more particularly, he discusses observations made on dove 

 embryos of the fourteenth and sixteenth day, and chick embryos 

 of the seventeenth and eighteenth day. He here states that 

 the sympathetic cells are multipolar, and that all the processes 

 have the character of nervous processes. He describes long 

 and short processes ; the latter end free within the ganglion, 

 the former pass beyond the bounds of the ganglion. In his 

 third communication Cajal retracts in part these statements, 

 and states that while the cells are multipolar, the great majority 

 possess one axis-cylinder branch, the others being dendrites. 

 In a brief account of his observations made on the sympathetic 

 ganglia of vertebrates, Retzius refers in a few lines to those 

 made on chick embryos of the fifteenth to the eighteenth day, 

 in which he merely confirms the conclusions ultimately reached 

 by Cajal as above given. 



Lenhossek has studied the sympathetic ganglia of embryo 

 chicks of the tenth and fifteenth day ; the best results were 

 obtained with the older embryos studied. 



In cross-sections of chick embryos of the above age, stained 

 after the double Golgi method, Lenhossek made the following 

 observations : — Both in the cervical and thoracic regions a ramus 

 communicans is wanting ; the sympathetic ganglion lies directly 

 on the median side of the ventral spinal nerve. In the thoracic 

 region the spinal nerve divides into a smaller dorsal branch and 

 a relatively larger ramus ventralis, on which the sympathetic 

 ganglion is found. These observations I can to some extent 

 corroborate on the grown chicken, although, as above stated, I 

 find the sympathetic ganglion, or a portion of it, resting on the 

 spinal ganglion. Lenhossek describes multipolar cells, with 

 one neuraxis and several dendrites, five to ten in number. The 

 dendrites are described as quite thick and relatively short, some 

 ending free without any branching. 



The neuraxes are described as taking one of three paths : 



i) Rarely into one of the peripheral branches of the ganglion 

 going to the viscera. 



