A Treatise on Astrology, Liber 536 by Aleister Crowley, 1917

Neptune in Aries

There is very little sympathy between the hard, practical, fire and energy of Aries and the cold sensitive Neptune. The combination makes for disruption; its aspect to another planet, other things being equal, is likely to be somewhat upsetting. Those aspects which we describe as good will be not so good when Neptune is in the sign, as if he is in one more harmonious with his nature. In all cases of war and other businesses requiring initiative and energy, the influence is likely to be particularly unfortunate. Neptune may be regarded as taking away all the good points of Aries, and replacing them by the very opposite qualities ~ the passive for the active, the soft for the hard, the sensitive for the forceful. In the particular technical case of the sailor, the indications are not so objectionable, though it seems unwise to entrust the welfare of a fleet to an Admiral with Neptune rising in Aries. Such an appointment could only be excused by some extraordinarily good aspects from such planets as Mars and Jupiter.

When Neptune is a determining force in questions of health, he will perhaps cause the affliction to take place in the head rather than in another part of the body. Rather than repeat this remark in every sign, one may briefly indicate here that it should be modified in each case by altering the word head to the part of the body indicated by the sign.