"Here it does, since it refers to life forces. The types are mutually, irreconcilably antagonistic. Your life forces are very strong. Thus, no matter how peaceable your intentions may be, many of our human beings would die before you would, but you will not live to get back to your ship if you land it and leave its protective insulation." "Why? What is it? How does it work?" Belle demanded. "It is not my business to know; only to tell. I have told. You will go away now." Garlock's eyes narrowed in concentration. "Belle, can you blast? I mean, could you if you wanted to?" "Certainly ... why, I don't _want_ to, Clee!" "I don't, either--and I'll file that one away to chew on when I'm hungry some night, too. Take her up, Jim, and try another shot." * * * Numbers Five to Nine, inclusive, were neither productive nor eventful. All were, like the others, Hodell all over again, in everything fundamental. One was so far advanced that almost all of its humanity were Seconds; one so backward--or so much younger--that its strongest telepaths were only Fours. The Tellurians became acquainted with, and upon occasion fought with, various types of man-sized monsters in addition to the three varieties they had seen on Hodell. Every planet they visited had Arpalones and Arpales. Not by those names, of course. Local names for planets, guardians, nations, cities, and persons went into the starship's tapes, but that welter of names need not be given here; this is not a catalogue. Every planet they visited was peopled by _Homo Sapiens_; capable of inter-breeding with the Tellurians and eager to do so--especially with the Tellurian men. Their strict monogamy was really tested more than once; but it held. Each had been visited repeatedly by starships; but all Garlock could find out about them was that they probably came from a world somewhere that was inhabited by compatible human beings of Grade Two. He could learn nothing about the faster-than-light drive. Number Ten was another queer--the Tellurians were found incompatible. "Let's go down anyway." Belle suggested. "Overcome this unwillingness of ours and find out. What do you think they've got down there, Clee Garlock, that could possibly handle you and me both?" "I don't think it's a case of 'handling' at all. I don't know what it is, but I believe it's fatal. We won't go down." "But it doesn't make sense!" Belle protested. "Not yet, no; but it's a datum. Enough data and we'll be able to formulate a theory." * * * "You and your theories! I wish we could get some _facts_!"