612 General Notes. [June, 
the second group, the former comprises all other Lamelli- 
branchs, 
_ Tue LATERAL Live oF Fisues.—It is familiarly known that the 
name of “lateral line” has been given by ichthyologists to an organ 
which runs along each side of almost all fishes, extending from 
the head to the tail. It has been successively studied by Steno, 
Lorenzini, Petit, Redi, Leydig and Schulze, the latter of whom 
have indicated the true path to be followed for the discovery of 
the functions of this line, whilst they have almost completed the 
investigation of its anatomy. 
M. de Séde, in a thesis recently maintained before the Faculty 
of Sciences at Paris, and reproduced in Cosmos les Mondes, 
gave an account of certain interesting experiments made for the 
purpose of elucidating the physiological functions of this curious 
organ. 
The fishes selected for the experiment were first submitted to 
the action of an anesthetic, and then underwent the operation of 
re-section of the lateral nerve, which excited no reflex action due 
to pain. When resuscitated the subjects were left at rest ina 
large bowl, and some days afterwards they were placed in a vast 
aquarium where everything is so arranged that a fish desirous of 
circulating freely must make use of all its tactile resources and 
means of guidance. Under these conditions it was observed that 
the fishes which had been operated upon moved only with great 
caution, and were almost always the last to arrive at the distribu- 
tion of food. Thus it appears that a fish able to make use of its 
eyes, but deprived of its lateral line, experiences a certain diffi- 
culty in finding its way. 
__M. G. de Séde next sought to ascertain how a fish would act 
if it retained the use of its lateral line, but was deprived of sight. 
Two perches were blinded by removal of the eye-ball. There 
remained to them, then, for guidance, merely. the general sensi- 
bility of the integuments and the special impressionability of the 
lateral apparatus in question. These organs. acquire in a short 
time a great delicacy, for the two perches, when placed in the 
general aquarium, were soon able so guide themselves without 
any difficulty. : 
But the question now arises as to what part of this steering 
power belongs to the general sensibility, and what to this lateral 
line? Further experiments solved this problem. 
A barbel was blinded, and, by way of extra precaution, its fila- 
ments were amputated. Subsequently its lateral nerve was 
severed. As long as this fish—even though deprived of its eyes 
and beard—retained the lateral nerve it guided itself easily ; but 
~ as soon as this nerve was severed, it remained persistently mo- 
— 3 Lastly, a perch, blinded and deprived of its lateral line on one 
