238 Papers from the Department of Marine Biology. 



but it seemed from its "feel" that each shock was a single wave, one 

 such as is portrayed on the plates prepared by physiologists in series to 

 represent the intermittent current of the ordinary shock given by the 

 fish. 



We are now ready to take up and discuss the questions on pages 231 

 and 232 and see what the experiments show. 



1. Is there an orientation of the plasmosome? A glance at the 

 table, in the fourth column, will show that there is. Also that it is a 

 more or less variable fact, in this torpedo reaching from some specimens 

 in which no orientation appears up to specimens in which, as in our 

 large American form, Tetronarce occidentalis, the percentage is about 

 100. 



2. Is this orientation due to the immediate physiological activities 

 which accompany nerve discharge? This certainly does not seem to 

 be the case. Fish of all sizes were examined after being killed both 

 by " vivisezione " and by being allowed to die without giving shocks, 

 and the table shows that neither a condition of ventral orientation 

 nor the reverse can be predicted by the method employed in killing 

 or by the amount of activity shown by the fish's electric apparatus 

 previously to the death of the specimen. In fact, strong negative and 

 positive reasons exist which indicate the reverse of this, Magini's main 

 contention. Twenty-five of the experiments were with fish that were 

 killed by the knife. In many cases they were persuaded to give many 

 shocks before being killed. In 2 cases all of the brain was used for 

 other experiments, so that we have remaining 23 cases to consider and 

 analyze. 



In these 23 cases, Nos. 1, 3, 4, 6-16, 18, 20-24, 27, 29, and 30, we have 

 all degrees of orientation, from less than 5 per cent in such cases as Nos. 

 9, 10, and 24 up through 10 per cent, 20 per cent, 70 per cent, and 

 85 per cent to a nearly perfect ventral orientation, as in the American 

 Tetronarce. This clearly makes it impossible to agree with Magini in 

 this regard, for we can not see in the table any consistent agreement 

 between the amount of immediately previous physiological activity 

 of the electric organ and the amount of ventral orientation of the 

 plasmosome. Nos. 9, 24, 27, and 29 show fish that were forced to use 

 the electric organ to excess just previous to death, and yet both showed 

 only 5 per cent of ventral orientation of the plasmosome. Also, Nos. 

 7 and 8 were killed according to Magini's method, but they show no 

 orientation. 



Looking at the other side of this factor, we find on the list several fish 

 which died quietly without using their electric apparatus to any extent 

 before death. Again we find that a quiet, inactive death has not 

 resulted in all cases in a lack of ventral orientation. No. 2 was chloro- 

 formed and shows 65 per cent; No. 19 died according to Magini's 

 formula and happens to show only 10 per cent; but passing to Nos. 



