What's the meaning of tricks of the nerves in this sentence?

Solution 1:

https://archive.org/stream/homeloverslibrar02mard/homeloverslibrar02mard_djvu.txt

Full text of "The home lovers' library (Vol. 2) by Marden, Orison Swett, 1848-1924, ed

Some women put themselves into a thoroughly unwholesome condi¬ tion during pregnancy by their fear of antenatal impressions. Many are the fearsome stories told in the twilight by old wives, and withheld ostentatiously from pregnant women. If antenatal impressions have any power over the unborn child — and this is by no means scientifically proved — it is through the nervous system of the mother. Her brooding is the only danger. The strongest nerves are not altogether controlled at such time, and therefore it behooves every woman to accustom her¬ self to sane thoughts on this subject, and to sane and wholesome activ¬ ities during the nine months. Work, and enough, though not too much of it; work, to the point of natural fatigue and sound sleep, though not to the point of nervous strain; this is the best antidote for all such tricks of the nerves. It keeps the mind to its proper function, and does not give it time to flee frantically from phantoms.

Solution 2:

Some definitions w/ examples:

nerves - The bodily state resulting from the influence of mental or physical stimuli, esp. with regard to a person's feeling or courage. Also, disordered or heightened sensitivity; anxiety, fearfulness, tension, etc.

• Shorter Oxford English Dictionary

He suffered an attack of nerves.

On the opening night at the Coliseum my nerves were wound tight like a clock.

trick - A mischievous act; A ludicrous or grotesque act done for fun and amusement.

• Shorter Oxford English Dictionary

• WordWeb

Note well, there are other definitions which may work here, but I don't feel they are as close or precise in meaning. E.g., "a special technique". Or, " A peculiar trait or characteristic".

Coalescing these, we may infer the meaning:

A mischievous and grotesque act of the nervous system rendering the subject highly anxious or fearful.