For Dexter, the initial kiss he shares with Judy is representative of a culmination of his dreams. From the first moment he saw Judy, there was something alluring about her. Dexter's love of Judy is driven by both what she represents and who she is. In this, the kiss is the realization of this vision. It is the embodiment of his pursuit. The kiss that he shares with Judy is an instant in which he can physically hold the result of his endeavors. It is a moment, and in this moment, there is complete immersion.
Fitzgerald notes as much in his description of the kiss that both of them share. This instant is symbolic of so much:
There was a pause. Then she smiled and the corners of her mouth drooped and an almost imperceptible sway brought her closer to him, looking up into his eyes. A lump rose in Dexter’s throat, and he wanted breathless for the experiment, facing the unpredictable compound that would form mysteriously from the elements of
their lips. Then he saw- she communicated her excitement to him, lavishly, deeply, with kisses that were not a promise but a fulfillment. They aroused in him not hunger demanding renewal but surfeit that would demand more surfeit… kisses that were like charity, creating want by holding back nothing at all.
Fitzgerald sees Dexter as understanding the symbolic meaning of the kiss in this passage. The notion of "fulfillment" is evident here. The kiss is the "fulfillment" of his dreas. The use of science as a metaphor is symbolic of how Dexter sees the kiss as the result of a scientific experiment, data that confirms his being in the world. Finally, the kiss is symbolic of "surfeit," or that excess which becomes so much a part of Dexter's love of Judy and the 1920s, in general.