76 Wisconsin Academy of Sciences, Arts and Letters. 



the imbedded cord. Proportional results are probably not 

 impaired by this fact, although the exception to the series 

 seen in No. 36 may rest on some irregularity in shrinking 

 during imbedding. 



A comparison of cells per mm. in brachial and lumbar re- 

 gions may be interesting. 



TABLE XIX. 



Frog, No 



Weight of frog, grammes 



^11 brachial . 



Cells, per mm. ^Cj^j^^^^. _ 



42 



111 



1663 



784 



The cells lie more closely than in the brachial region, and 

 the number of cells decreases per mm. with the growth of 

 the frog more rapidly in the lumbar than in the brachial re- 

 gion. This fact is plain also in the outer form of the cord 

 which gradually changes from a conical to a cylindrical 

 form. The change is also more rapid in youth than later. 



III. Relation of Motor Cells and Fibres. 



In frog No. 43, the motor fibres of the right sids and the 

 cells were both counted as given in the preceding pages. 



The number of motor fibres in the ten nerves on the right 

 side was 5,734. 



The number of ganglion cells was, right, 5,777; left, 5,740. 

 The correspondence is so close that we can well conclude 

 that for each motor nerve fibre there is present a ganglion 

 cell in the anterior horn of the cord, and that all ganglion 

 cells therein contained are connected with motor nerve fibres. 



Other countings gave the following result: 



TABLE XX. 



No. of Frog 



Motor Fibres of one side . . . 

 Ganglion Cells of right side 

 Difference 



42 

 5,734 



5,777 

 -43 



