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c. 1878


INVENTOR: Aaron Hodgkin Cole, Chicago

MAKER: Queen and Co.

cole's frog plate
cole's frog plate
cole's frog plate


This is a rare wooden frog plate invented by Aaron H. Cole. It is signed 'Coles Self-adjusting Frog Plate.'   It measures about 4 7/8 inches long and 1 7/8 inches wide. It has two long brass spring clips held in place by a brass plate to hold its bottom on a stage. There are fifteen brass brads to wrap the thread around when securing the specimen. There are two short clips at the round end and one at the straight end, as well as two on the sides just before the curve, to hold the ends of the thread in place firmly enough to keep them in place but loosely enough that they can 'self-adjust.'   The wood is about 1/4 inch thick. One big advantage of this design is there are no tiny holes to deal with when using thread to secure the specimen.



JRMS frog plateAs shown to the left, this frog plate was reported in the JRMS of 1886. In 1883, this Frog Plate was recommended in Queen and Companies Microscopical Bulletin and Science news. In 1885 it was sold by Queen and Company for $1.25. Aaron Hodgkin Cole of Chicago, (not to be confused with the famous British mounters Arthur C Cole and Martin J Cole), was an Extension Lecturer for the University of Chicago and a biology teacher at Lake High School also in Chicago. In 1902 he published a paper in the Journal of the National Education Association entitled 'Projection Microscope: its possibilities and value in teaching Biology.' In 1905 he presented a paper to the National Education association and reported in their proceedings of 1905. This paper described the utility of the projection microscope, for 'Teaching Biology from Living Plants and Animals' using an electric arc lamp as the illuminant. In 1907 he published a book entitled 'Manual of biological projection and anesthesia of animals.'   In this book, he explained how he relied heavily on anesthesia to immobilize his specimens,(including frogs), and used a simple glass plate on which to view the circulation of the blood in the web of the frog foot, since no restraint was needed. Apparently by this time, he did not need to use the frog plate which he himself had invented.