There are many topics connected with this subject to which I should feel disposed to advert, did time permit; but, limited as we are, I could not do justice to them. I shall therefore only remark, that there seems little appearance of any unanimity of sentiment here. I think it is an error to come here with a preconceived idea or theory, determined to abide by it, and so force facts as to make them accord with it In fact, no single theory, nor any of those laid down, will serve to satisfy the requirements in the various forms of parasitic fungi, and the destruction by them of plants, fruits, and grains. The causes that will account for the vine mildew will fail to explain the pear fungus, or disease in the apple, pea, or gooseberry. The circumstances under which these various forms of organized life are propagated and developed are different, though the nature of their growth is similar. There are many various forms of them, many entirely distinct in their operation. As to the cracking of the pear, one of the most conclusive evidences of this is the fact, that until all the various theories were exhausted and disproved by a variety of circumstances, the freedom of the White Doyenni from cracking, in city yards, first led to the acceptance, in this country, of the statement made years ago by Berkeley, that this was caused by a parasitic fungus.

The truth was rejected as long as possible, but in no other way could this fact be accounted for, that the fruit was exempt in cities, where the trees were not subject to the fungus floating in the atmosphere. While I see no probability of agreement of opinion, I believe I can see my way somewhat more clear through the arguments adduced, and this is at least a benefit. Much of the information possessed by gardeners, on this and similar subjects, must be from reading and study, not alone from personal research; time and means do not permit them to investigate scientifically in many branches; therefore they must, if they search at all, accept the opinions of those in whom they think they can place confidence. This, I admit, has been my own course. The information on crypto-gamic botany I have gathered, has been from the researches of others chiefly, with such observations in the nursery and garden as I could make; much, however, can be learned in this way, and I do not think it right here to ignore all greater authorities, and confine us to our own observations in questions of this nature. With respect to several arguments used in the course of the remarks this evening, I have something to say.

I can not believe that parasitic fungi only occur on diseased tissue; nor that a dry, arid atmosphere is congenial or favorable to the development of their minute sports or mycelia. I believe, from all that I have seen and learned, that moisture, at least in their nascent state, is the desirable and essential condition, generally; there are exceptions: that after the fungus has been developed and extended through the tissue, that it matures, throws up its fruit spores, is then visible; and if a hot sun succeeds, and acts on it, will become brown, and the tissue of the leaf will be destroyed. Wo should not confine ourselves to one or two forms, but reason from a full knowledge of facts.