Fetal bovine serum the harvesting of blood from the bovine fetus after the fetus is removed from the slaughtered cow. The blood is collected aseptically into a sterile container or blood bag and then allowed to clot. The normal method of collection is cardiac puncture, wherein a needle is inserted into the heart. This minimizes "the danger of serum contamination with micro-organisms from the fetus itself, and the environment". It is then centrifuged to remove the fibrin clot and the remaining blood cells from the clear yellow (straw) colored serum. The serum is frozen prior to further processing that is necessary to make
Blood, Sweat & Tears (Blood, Sweat & Tears album) City. The studio had just taken delivery of one of the first of the model MM-1000 16-track tape recorders, built by Ampex. The new technology allowed for far more flexibility in overdubbing and mixing than the 4 and 8-track tape recorders which were standard in 1968. The album was among the very first 16-track recordings released to the public. An additional song, "Children of the Wind" was recorded for the album but was not included. It later appeared on the compilation, "The Very Best of Blood, Sweat and Tears: What Goes Up!" The album was selected for the 2006 book