20 
MESMERISING LOBSTERS AND OTHER 
CRUSTACEANS. 
It is known to a number of people at least that a lobster 
may be put into a comatose condition by rubbinji- it alono- the 
back of the carapace. The usual way is to hold the lobster 
head down with the claws arranged so as to form a support 
with the rostrum and to stroke it rapidly as stated with the 
tips of the fingers. In about a minute it will be found that 
the lobster will succumb and it Avill remain without move- 
ment in this position for a long but variable period. The 
Laboratory attendant, J. A. Taylor, pointed this out to me 
last year. And at my request he tried with success the same 
operation upon the Norway- Lobster and the common Crab. 
With a view to seeing whether the reversed position , as deter- 
mining the blood to the head, was essential, a lobster was 
treated in the horizontal attitude and so successfully that it 
remained without movement for three hours and was then 
awakened. A Norway Lobster similarly treated was quiescent 
for 55 minutes. It was found also that a lobster could be 
put to sleep on its back. The crab goes to sleep usually in 
the tucked-up condition — and may be left in the natural 
position or on its back. They all recover when disturbed, 
but in the case of the lobster this appears to be hastened by 
rubbing the under surface of the cephalothorax. Recovery 
is immediate when the lobsters are placed in sea water. In 
the case of the crab one at all events took some ten minutes 
after being returned to the water to come round completely. 
During the sleep the scaphognathite is in action all the 
time and there may be movements of the appendages as well. 
Reflexes take place also. 
