"The manual is a codex of denial, submission, ignorance, boredom, tiredness, exasperation and triviality so far as sexuality is concerned for women—there is no hint of pride, or of enjoyment." It's a vintage medical hard sell!
There's a really interesting discussion on the Ptak Science Books blog about the zeal with which 1920s doctors treated women's fainting spells — generally code for: "has a headache." As the author points out, certain words were always delicate "medical" code for "disinterest in sleeping with husband."
Globeol addresses the keyword problems for sexual malaise: "debility, overstrain, anaemia, nervous exhaustion" by "conversion into pure, strong, health-giving blood". Lest the use of STRONG BLOOD PURE BLOOD-FORMING HEALTH-GIVING GOOD SOWER be lost there is always the Johnny Appleseed person above, casting about his seed, growing children instantly.
I might be completely wrong on this but, really, I like the possibility of this weird approach's explanatory power—it doesn't take a philo-shrinkologist to see the conjoined symbolisms in this set of ads and the approach to unmentionable complaints, and that's what I think is exactly going on here.
I think it's a pretty convincing argument - particularly given that the other complaints which these remedies would have treated - "rheumatism, migraine, acidity, obesity" - couldn't have been exactly aphrodesiacal.
Then too, there's a long history of doing exactly the opposite: using explictly (if delicately coded) sexual stimuli to treat women's "neuresthenia." This is the premise of Sarah Ruhl's play In the Next Room: Or, The Vibrator Play, which follows a 19th Century doctor as he treats a range of women for "hysteria" by inducing orgasm electronically.
Of course, both sides of the coin lay the blame - or at least the treatment - squarely on the same women whose "vitality" might well have been sapped by constant child-bearing. As the PSB points out, "Suspension of sexual discussion and understanding aside, it was well understood that women's sexual nature was completely repressed unless in response to the pleasure of men. It was a story of submission and subjugation, with all responsibilities for failed masculine sexuality falling to the shoulders of women (as clearly stated in the still-popular Stall's marriage manual, a 19th century piece of rusty thinking still serving as the standard bearer in the early 20th century)."