LIVING TORPEDOS IN BERLIN. 



515 



and equal transverse section 1 . As regards the details of the method, 

 I refer to the description given at that time. But in order to 

 make it more readily understood, and inasmuch as the apparatus 

 in all its simplicity has proved well suited to our object, I add a 

 diagram of it in Fig. 21 in a somewhat more perfect form. The 

 new apparatus differs in some points from my original model. It is 

 unessential that the funnels, which, filled with physiological clay, 

 connect the base of the tube containing the tissue etc. with the 

 leading-in pads, are made of vulcanite instead of gutta-percha, and 

 are supported by brass pillars well lackered ; it is of greater im- 

 portance that the diameter of their apertures very little exceeds the 

 thickness of the pads ; hence the side of each cone is still only 

 13-5 mm. long. Their resistance is thereby considerably diminished, 

 and this is advantageous, in so far as it is desirable that the resist- 

 ance of the rest of the circuit should be as small as possible in 



Fig. 21. 



comparison with t'hat of the conductor of which the resistance is to 

 be determined. In the figure, it is easy to recognise the funnel 

 filled with clay, drawn on the left in elevation and on the right 

 in section, between the leading-in vessels and the resistance tube 

 fixed between the funnels. 



The tubes previously used, 2,5 mm. in length, with an internal 

 diameter of 4-6 mm. are exactly suited for the M. gracilis of a frog, 

 3 1 cm. in length from the tip of the nose to the longest toe, a 

 medium size readily found in this country 2 . I still had the very 

 same tubes in my possession ; it was found that they had also the 

 length and breadth suitable for organ preparations. In order to 

 introduce these into the tubes so as to fill them completely, I drew 



1 Joh. Eanke. Tetanus. Eine physiologische Studie. Leipzig, 1865, p. 44. 



2 Ueber secundar-elektromotorische Erscheinvmgen. Sitzungsberichte, 1883, vol. i. 

 P- 355- 



