Is this liquefaction a deliquescence? Most assuredly not.
1. The substance within the ampulla—the indurated blood—so far as the eye can judge of it, through the glass of the ampulla and the glass sides of the reliquary, bears no resemblance to any of the substances which are known to deliquesce.
2. The process of deliquescence is well known and is not to be mistaken. It is gradual; and the exterior of the deliquescing substance, being in immediate contact with the water-bearing atmosphere, is always seen to yield first to the liquefying influence of the water. On the contrary, the liquefaction is often instantaneous—in un colpo d’occhio; in un tratto. Even when gradual and not instantaneous, the differences are marked. The upper portion will become perfectly liquid while the lower portion remains still hard; or the lower portion will liquefy while the upper portion retains its hardness; or, again, the upper and lower portions may both remain hard while the middle portion becomes fluid; or the middle
portion will continue hard and solid while they become perfectly liquid: sometimes, the outer surface next to the glass sides of the ampulla will be seen to soften and liquefy first—in this case following the course of a deliquescence; sometimes precisely the reverse occurs—the central portion is seen to become liquid while the exterior remains hard and unliquefied. When we add that occasionally one side or lateral half liquefies while the other preserves its hardness, and also that, while frequently the entire mass becomes liquid, yet, on many occasions, a certain portion remains hard for hours and days and then liquefies—perhaps gradually, perhaps only after the entire mass has become hardened again—it will be seen that this liquefaction presents every possible mode and shade of difference to distinguish it from the single mode of deliquescence.
The difficulty becomes greater if we consider the obstacles to a freer communication between the outer atmosphere and the substance within the ampulla. The ampulla is a tightly-closed glass vessel, and is itself held within the reliquary, another tightly-closed vessel of metal and glass. This twofold barrier must forbid any ready and rapid passage of atmospheric water from the air to the substance within the ampulla.
Again, no connection whatever can be discovered between the superabundant moisture or the dryness of the atmosphere at Naples and the occurrence or non-occurrence of the liquefaction. We may take a series of twenty days, which the diary marks as very rainy, or occurring in a long-continued rainy season; and a series of twenty others, when the weather was dry—so dry, they were praying for rain. It will be seen that the phases of the liquefactions for
each series are so alike that they might be interchanged. The general hygrometric condition of the atmosphere evidently has no perceptible influence for or against or on the liquefactions.
Nay, more, it frequently happens that the blood, after liquefying, grows solid again on the same day, and then liquifies, perhaps solidifies anew, and liquefies a third time. All these changes have sometimes taken place within one hour. Now, did the atmosphere, during that hour or during that day, pass through corresponding extreme changes of its hygrometric condition? Ordinary men did not feel them. Meteorological observers have not noticed them. Registering instruments do not record them. And yet, the habit of watching their neighboring and often threatening volcano has made the people of Naples as observant of such changes as sailors at sea, and has given to that city one of the ablest schools of meteorology on the Continent.
We may well conclude, therefore, that the liquefaction of the blood of St. Januarius is not the deliquescence of a solid body, arising from humidity of the air to which it is exposed.
Is it the melting of a solid substance through the action of heat?