Magic Numbers in MD5

I am curious where some of the magic numbers in MD5 originated. First, we have the four chaining variables, A, B, C, and D which are initialized with apparently random numbers. Are they as random as they look, or are they carefully chosen? Second, we have the t_i values. Schneier's first edition says this: "In step i, t_i is the integer part of 4294967296xabs(sin(i)), when i is in radians. (Note that 4294967296 is 2^32.)" Does abs(sin()) have some properties that are especially conducive to strengthening MD5 or is it just a function to generate mildly random numbers? If the latter, wouldn't the algorithm be stronger if it was used with completely random numbers? Peter Hendrickson ph@netcom.com