When I state that there are six or seven miles run of mushroom-beds in the ramifications of this cave, and that the owner is but one of a large class who devote themselves to mushroom culture, the reader will have some opportunity of judging of the extent to which it is carried on about Paris. These caves not only supply the wants of the city above them, but those of England and other countries also, large quantities of preserved mushrooms being exported, one house alone sending to our own country no less than 14,000 boxes annually. There were some traces of the teeth of rats on the produce, and it need not be said that these enemies are not agreeable in such a place; but they did not seem to have committed any serious ravages, and are probably only casual visitors, who take the first opportunity of obtaining more varied food than is afforded them by these caves. To traverse the passages any further is needless--there is nothing to be seen but a repetition of the culture above described, every available inch of the cave being occupied. We again find our way to the bottom of the shaft, carefully mount the rather shaky pole one at a time, and again stand in the hot sun in the midst of the ripe wheat. In traversing the fields two things relating to mushroom culture are to be observed--heaps of white gritty earth, sifted from the _débris_ of the white stone, and large heaps of stable manure accumulated for mushroom growing, and undergoing preparation for it. That preparation is different from what we are accustomed to give it. It is ordinary stable manure, or very short stuff, not droppings, and is thrown into heaps four or five feet high, and perhaps thirty feet wide. The men were employed turning this over, the mass being afterwards stamped down with their feet, a water-cart and pots being used to thoroughly water the manure where it is dry and whitish. As many will feel an interest in the cave culture of the mushroom, and perhaps wish to see it for themselves, I may state that it is difficult to obtain permission to visit the caves, and many persons would not like the look of the “ladder” which affords an entrance. Even with a well-known Parisian horticulturist I had some difficulty in entering them. I was informed that one champignonniste in the same neighbourhood demands the exorbitant price of twenty francs for a visit to his cave. As the visit is the work of some little time, no visitor should put the cultivators to this trouble without offering some slight recompense--say not less than five francs. The above cave is but a sample of many in the immediate neighbourhood of Paris.