The demand for Guinea Pigs as pets is very large. They are so widely used in the medical field that the pet stores have a hard time keeping enough on hand to supply the local demand for pets. They are very interesting and perfectly harmless little animals. No animal so well adapted for scientific experiments as the Guinea Pig. In the testing and analyzing of serums and antitoxins and for experimental purposes generally the demand is enormous, thousands and thousands of them being used every year. Many of the large hospitals and laboratories have been compelled to establish breeding pens of their own in order to be sure of a constant supply. The demand here is steadily increasing and many more would be used if they could be obtained at a reasonable price.