The poem _Cristina_ (1842), while not very remarkable as poetry, is notable because it contains thus early in Browning's career, four of his most important doctrines. The more one studies Browning, the more one is convinced that the poet's astonishing mental vigor is shown not in the number and variety of his ideas, but rather in the number and variety of illustrations of them. I can not at this moment think of any poet, dramatist or novelist who has invented so many plots as Browning. He seems to present to us a few leading ideas in a vast series of incarnations. Over and over again the same thoughts, the same doctrines are repeated; but the scenery, the situations, and the characters are never alike. Here is where he remains true to the theory set forth in _Transcendentalism_; the poet should not produce thoughts but rather concrete images of them; or, as he says in the closing lines of _The Ring and the Book_, Art must do the thing that breeds the thought.
In _Cristina_, four of Browning's fundamental articles of faith are expressed: the doctrine of the elective affinities; the doctrine of success through failure; the doctrine that time is measured not by the clock and the calendar, but by the intensity of spiritual experiences; the doctrine that life on earth is a trial and a test, the result of which will be seen in the higher and happier development when the soul is freed from the limitations of time and space.
The expression "elective affinities" as applied to human beings was first brought into literature, I believe, by no less a person than Goethe, who in his novel, published in 1809, which he called _ Elective Affinities (Wahlverwandschaften_), showed the tremendous force which tends to draw together certain persons of opposite sexes. The term was taken from chemistry, where an elective affinity means the "force by which the atoms of bodies of dissimilar nature unite"; elective affinity is then simply a chemical force.
In Goethe's novel, Charlotte thus addresses the Captain: "Would you tell me briefly what is meant here by Affinities?" The Captain replied, "In all natural objects with which we are acquainted, we observe immediately that they have a certain relation." Charlotte: "Let me try and see whether I can understand where you are bringing me. As everything has a reference to itself, so it must have some relation to others." Edward interrupts: "And that will be different according to the natural differences of the things themselves. Sometimes they will meet like friends and old acquaintances; they will come rapidly together, and unite without either having to alter itself at all--as wine mixes with water." Charlotte: "One can almost fancy that in these simple forms one sees people that one is acquainted with." The Captain: "As soon as our chemical chest arrives, we can show you a number of entertaining experiments, which will give you a clearer idea than words, and names, and technical expressions." Charlotte: "It appears to me that if you choose to call these strange creatures of yours related, the relationship is not so much a relationship of blood as of soul or of spirit." The Captain: "We had better keep to the same instances of which we have already been speaking. Thus, what we call limestone is a more or less pure calcareous earth in combination with a delicate acid, which is familiar to us in the form of a gas. Now, if we place a piece of this stone in diluted sulphuric acid, this will take possession of the lime, and appear with it in the form of gypsum, the gaseous acid at the same time going off in vapour. Here is a case of separation: a combination arises, and we believe ourselves now justified in applying to it the words 'Elective Affinity;' it really looks as if one relation had been deliberately chosen in preference to another." Charlotte: "Forgive me, as I forgive the natural philosopher. I can not see any choice in this; I see a natural necessity rather, and scarcely that. Opportunity makes relations as it makes thieves: and as long as the talk is only of natural substances, the choice appears to be altogether in the hands of the chemist who brings the creatures together. Once, however, let them be brought together, and then God have mercy on them." The scientific conversation is summed up by their all agreeing that the chemical term "elective affinities" can properly be applied in analogy to human beings.