One must be careful to either press the core-containing needle straight down onto the "blot paper" or lightly press the "blot paper" down onto the core-containing needle. Either way, the two should be lifted straight apart from each other in delivering the tissue core to the "blot paper". If one slides or wipes the two apart, the core can be inadvertently "somersaulted" out of the needle, "flipping over" onto the arrow mark of the "blot paper" in such a way that the correct orientation of the core ends is reversed. Therefore, the pathologist must pay careful attention to microscopic features: if the biopsy operator (correctly) does not push the needle into the gland before "firing" the biopty gun (just gently "snuggs" the tip into the capsule), then the core will often contain a fibromuscular-fatty (capsular) boundary at one end.