An explicatory essay, I believe, is the same as an explanatory or interpretive essay, where the teacher/professor expects the student to respond to something, in this case the short story, "Gooseberries" in the form of explanation or interpretation.
If I were writing about "Gooseberries," I would write something similar to the following:
Ivan visits with his brother and the visit changes Ivan. (This is the topic of the essay.)
My interpretation of the story is that Ivan's brother Nicholai, scrimps and saves, and sacrifices even the most basic pleasures in life, such as having enough to eat, to the dream of having a farm. By the time he has his farm, his youth is gone, and he is old and worn out, but beyond that, he now feels that he is better than everyone else, even though his own family is descended from "peasant stock." He imagines himself to be much greater than he is, while forgetting that in his "happiness," such as it is, that he has a responsibility to those who are without--those who suffer silently, behind the scenes.
When Ivan sees how his brother acts, he becomes fixated on how he should be helping others, and that no one can be truly happy if he remembers the less fortunate; it is every man's responsibility to help those who are not so blessed.
Ivan shares this information with Aliokhin (their host overnight) and Bourick, the school master. That night, Aliokhin seems generally unmoved by the story, and excuses himself to go to his room to sleep. (After all, he has a nice home with a beautiful young woman to keep house for him: what could be wrong with his life?)
However, Bourkin cannot sleep, outwardly thinking it has something to do with the smell of his pipe, an inconsequential thing, as the rain pours down on the roof above. I believe (interpretation), however, that it is because Ivan has planted the seed of social responsibility in Bourkin's heart, and that the school master, an educated and knowledgeable man, is unsettled about the philosophy Ivan has presented him with, without being aware of it.
In drawing a conclusion to this essay (once again, my interpretation), I would point out that happiness does not come without a price: to pass on one's good fortune to others. After all, with the slightest change in our own good fortune, we could be struggling as others do, every day.
This type of essay examines how a piece of writing has been crafted; that is, why the writer chose to include the details he or she did, how certain words achieve an effect, or why a plot is organized the way it is, and what effect it brings about. Usually, explication is a detailed examination of a work, line by line. For that reason, it is usually limited to a short poem or a short selection from a longer poem, story, or novel. Explication makes what is implicit in writing, explicit. These types of essays do not usually go over 100 words.
To explicate an essay or paper one has to slowly unfold the meaning of text, moving slowly from passage to passage. In some cases one has to move from line to line of a verse or a poem or even read between the lines to fully explicate the text. Due to a relatively small size of this type of essay, all explication essays must have sharp focus. You need to concentrate on the central theme, the climax and the turning points of the chosen text. It is only through a close reading of one scene, students can unfold the story's meaning as fully as they can.
Explicating is about slowly revealing the meaning of some passage, verse, poem or text. The first step is to identify key scenes, a statement of theme, a crucial conservation as well as opening and closing sections of the chosen piece of literature. The other step is to interpret the passage in a sequential (step-by-step, line-by-line) manner.