OCTOPUS ARM, REGENERATION AND STRUCTURE 9 
Among the animals which were delivered to me for experimental 
purposes at Naples and Monaco, I also found a great many 
whose arms had been injured before capture, and quite a number 
of them showed advanced stages of regeneration. This shows 
plainly that the loss of an arm is by no means a rare or adangerous 
occurrence. If, however, an animal, which is subject to frequent 
injuries on a certain part of its body, would each time bleed from 
five to six hours, the loss of blood would in the end probably 
prove fatal. The fact that the animals easily survive frequent 
injuries of their arms indicates the improbability of such pro- 
longed bleedings. 
It is difficult to explain the tardy appearance of blood on the 
wound. The only explanation I can give is the following: The 
minute the arm is cut off or cast off by autotomy the blood- 
vessels contract at the wound, later the muscles of the blood- 
vessels relax and allow blood to flow. The blood-corpuscles 
soon form a clot (agglutinate), and this clot serves as a prelimi- 
nary covering for the wound. 
Figure 7 which in comparison to figure 6 presents quite a differ- 
ent picture, exhibits a completely covered or closed wound. 
The time in which complete healing of a wound is achieved varies 
greatly. Some wounds were healed within less than twenty-four 
hours after operation, others showed no healing after thirty 
hours and were at that time only covered with a blood clot. The 
differences in the time necessary for the complete healing of the 
wound are probably caused by various factors. Generally a 
wound in the distal portion of the arm healed more quickly than 
one located in the middle or at the base. It is quite likely that 
the age of the animal also plays a part, for the wound healed 
more rapidly in a younger animal than in an older one. The 
season of the year may also have some influence on the progress 
of wound healing. In Naples, where I experimented in the 
spring, I found that the wound healing took less time than in 
Monaco, where I carried on my experiments in the fall of the 
year. 
Figure 7 shows a perfectly smoothly healed arm stump. This 
smooth appearance is probably due to the wound’s having been 
