A calculated measurement in which the weight, that is, the heaviness or the force with which a body is drawn toward earth by gravity, of the beta cells in the tail region of the pancreas is derived by multiplying the weight of the entire tail region of the pancreas by this fraction: [average cross-sectional area of pancreatic islet beta cells in the tail region divided by average cross-sectional area of the tail region of the pancreas]. The tail region of the pancreas is the portion of the pancreas which lies furthest from the major pancreatic duct and closest to the spleen, the highly vascular lymphoid organ which serves to store blood, disintegrate old blood cells, filter foreign substances from the blood, and produce lymphocytes. The pancreas is the elongated, racemose gland containing both endocrine and exocrine elements which secretes hormones such as insulin and glucagon internally and digestive enzymes externally. A pancreatic islet is a small encapsulated region of the pancreas containing endocrine (i.e., hormone-producing) cells. An islet beta cell is a membrane-enclosed protoplasmic mass constituting the smallest structural unit of an organism that is capable of independent functioning, which is found in a pancreatic islet and produces the hormones insulin and amylin. Area is the value representing the size of the two-dimensional extent of an object.