I got into the subject of anomalies in an indirect way, through exploration during 1967-1968 of the speculative idea that the muon-electron mass difference could be accounted for by giving the muon an additional magnetic monopole electromagnetic coupling through an axial-vector current, which somehow was non-perturbatively renormalized to zero. After much fruitless study of the integral equations for the axial-vector vertex part, I decided in the spring of 1968 to first try to answer a well-defined question, which was whether the axial-vector vertex in QED was renormalized by multiplication by Z2, as I had been implicitly assuming. At the time when I turned to this question, I had just started a 6-week visit to the Cavendish Laboratory in Cambridge, England after flying to London with my family on April 21, 1968.a In the Cavendish I shared an office with my former adviser Sam Treiman, and was enjoying the opportunity to try a new project not requiring extensive computer analysis; I had only a month before finished my Annals of Physics paper  on weak pion production, which had required extensive computation, not easy to do in those days when one had to wait hours or even a day for the results of a computer run.
I wish to thank Peter van Nieuwenhuizen for a phone conversation clarifying this part of the history. In my 1998 Dirac lecture , and several archival historical accounts. I had written "My interest in the multiplicative renormalization question had been piqued by a preprint I received from Peter van Nieuwenhuizen, in which he attempted to show that the axial vector vertex is made finite by the usual renormalizations, using an argument based on subtractive renormalization that I saw was incorrect." On reexamining my files in the course of preparing this article, I found that my copy of van Nieuwenhuizen's undated preprint entitled "Finiteness of radiative corrections in all orders to /ti-decay" had been sent, in response to a letter I wrote to Veltman, by Veltman's secretary Ms. Rietveld, who wrote a cover letter dated May 28, 1968 expressing the hope that the preprint would reach me while I was still in England. Thus I could not have seen the preprint until the end of my stay in Cambridge. I do not have a copy of my letter to Veltman inquiring about a preprint version of van Nieuwenhuizen's talk, to which Ms. Rietveld's letter was a response.