the administration of concanavalin a ( con a ) ( 50-200 microgram/egg ) to chick embryos between the third and the seventh day of incubation has the following effects on the retina : ( 1 ) con a causes the degeneration of a large number of ganglion cells and consequently the layer that should be formed by these cells is not present or is constituted only by a small number of ganglion cells .
C0017067
ganglion
C0228071
ganglion cells