Real bookstore info here before the THOUGHT PROVOKING QUESTION. this is Treasure Chest, Vol. 24. Issues for sale are 2-10, 12, 14, 15-17. If interested in only a few issues let me know. Price(s) are negotiable. NOW THE QUESTION: can Superman catch a cold? If yes, then he's not invulnerable, right? But if no, then his body works differently than ours because over 50% of the cells in a human are not actually human cells. So do Kryptonians not have that kind of biology? Or does Supes" body have the ability to distinguish between good and bad biological interlopers? If so, then his blood should be regularly harvested and studied for use in helping humans develop that ability, and they surely could because Supes is able to survive in our atmosphere, eat our food, and create offspring with us, so our biologies must be very similar to Kryptonians' systems. I know Wikipedia probably has an answer to this but c'mon, this is a good thought experiment.