Little Johnny walked into the kitchen, saw his mother making a cake and announced, "I'll be playing in my room for the next two hours. I sure would like a piece of cake when you're finished."
Later, when his mother brought him a piece of cooled cake, Little Johnny exclaimed, "Golly, it worked!"
Puzzled, his mother asked, "What do you mean?"
Little Johnny replied, "Daddy said that in order to get a piece around here, you have to spend a couple of hours playing first!"
Dried blood serumIn 1933, dried human blood serum was prepared for the first time in the U.S. at the school of Medicine, University of Pennsylvania, Philadelphia, Pa. It was prepared by Drs. Earl W. Flosdorf, an experienced refrigeration engineer, and Stuart Mudd who created a glass apparatus to freeze-dry serum, the clear fluid in the blood that contains the proteins and antibodies formed by the body's immune system to protect against infection. The powdered, dried blood serum was used successfully for transfusions for the prevention of childhood diseases. The method was first described in April of the following year at a meeting of the American Chemical Society at St. Petersburg, Florida. Dried blood serum was used during WW II.[Image: detail from a photograph taken at an exhibit of the equipment. Shell-freezing unit far left, vacuum pump next to it, and next to it refrigeration trap to remove moisture from drying plasma. Metal cylinder in foreground serves as a drying chamber.] |
