This picture shows a vial of insulin produced in 1923, two years after insulin was discovered. It shows a 5cc glass bottle. The insulin is from Lab. No. 257-4, dated November 5 1923. The label on the front of the bottle reads: 'Insulin 10 units - 5 c.c. vial. 10 units per c.c. Connaught Laboratories. University of Toronto'. According to the Connaught anti-toxin laboratories filling records for insulin this bottle was filled November 1, 1923.
The dark color of the insulin may be doe to the insulin not being purified during the early years. Insulin was taken from pigs and cows, but not purified and made safe for injection purposes until the Lilly company took over and made the insulin safe by removing the impurities.