The following pictures exhibit mammary glands dissected from six separate mice in different stages of mammary morphogenesis and function. Each mouse was euthanized before their abdominal mammary glands were dissected and placed on microscope slides. After 5 minutes of drying on the microscope slide, the mammary gland dissections were immersed in Carnoy’s fixative for 4 hours to avoid further autolysis. Next the slides were washed in a series of solutions: 70% EtOH for 15 minutes, 50% EtOH for 15 minutes, 30% EtOH for 15 minutes, and distilled H2O for 5 minutes. Then the slides were stained in carmine alum overnight. Once the mammary glands were thoroughly stained, they were rinsed and dehydrated in another series of solutions: distilled H2O, 70% EtOH for 15 minutes, 90% EtOH for 15 minutes, 95% EtOH for 15 minutes, 100% EtOH for 15 minutes, and 100% fresh EtOH for 15 minutes. The specimens were then cleared in Histoclear for 3 hours. Permount mounting medium was used to mount the mammary glands. All pictures were taken through the tube of a histology microscope.