"Not at all. Alive and kicking."
"Alive after nine days? Oh! oh!"
"Here they are, in this glass. It is exactly nine days since they were cut off, and I have been watching them daily under the microscope. I assure you that I have seen them grow, not larger, indeed, but develop more and more, muscle fibers appearing each day where before there were none at all."
"Come, now, you are trying to see what a fool you can make of me."
"I am perfectly serious. The discovery is none of mine. It was made by M. Vulpian in Paris. He says that the tails live many days—as many as eighteen in one instance; but I have never kept mine alive more than eleven. He says, moreover, that they not only grow, as I have said, but that they seem to possess feeling, for they twist about with a rapid swimming movement when irritated."
"Well, but I say, how could they live when separated from the body? Our arms or legs don't live; the lobster's legs don't live."
"Quite true. But in those cases we have limbs of a complex organization, which require a complex apparatus in order to sustain their life. They must have blood, the blood must circulate."
"Stop, stop! I don't want to understand why our arms can't live apart from our bodies. They don't. The fact is enough for me. I want to know why the tail of a tadpole can live apart from the body."
"It can. Is not the fact enough for you in that case also? Well, I was going to tell you the reason. The tail will live apart from the body only so long as it retains its early immature form. If you cut it off from a tadpole which is old enough to have lost its external gills a week or more, the tail will not live more than three or four days. And every tail will die as soon as it reaches the point in its development which requires the circulation of the blood as a necessary condition."
"But where does it get food?"