This is going to sound odd, but a Terry Pratchett book lead me to look up the meaning of the word "fecund", and the result included a google ngrams graph of its use in written works.
As you can see, there's a pretty angular increase in its usage in the 1950s and 1960s, I was intrigued by this and looked a little further, I found this more detailed graph.
This was even odder information, because it looks like the increase I was interested in was due to an increase in the use of Fecund with an upper case F.
I've done some research, and I can't find evidence of someone named Fecund being written about in the mid 20th century. It also seems relatively unlikely to be used at the start of a sentence.
Was there someone well known called Fecund? Or perhaps a commonly quoted statement beginning a sentence with it? Why did this clear increase start and end so suddenly?