Retrospective Criticism. SIS 



or four days to the house ; that gentle syringings every two or three days, and 

 a slight covering of hay, were conducive to the growth of the mushroom. 



Mr. Fish believed that the nearer we imitated the works of nature, the 

 more successful would be our operations ; and that the more substantial a bed 

 is made, the more juicy and better would be the produce. 



Mr. Caie agreed with Mr. Fish in the observations just made, and in refer- 

 ence to that subject, he always observed that mushrooms were found more 

 plentifully after rain, and that showery after warm weather was the cause of 

 producing them. He has grown mushrooms on shelves, by filling them in 

 succession with well-prepared dung, and spawned, by which he produced a 

 regular supply nearly all the year round. He has known gentlemen's places 

 where the gardeners rarely succeeded in growing mushrooms. 



Mr. Massey considered any adhesive soil fit for making the brick, but would 

 give the preference to loam. He always made the best spawn with horse- 

 droppings, cow-dung, and loam; he has kept it for nine years. He always 

 observed the new spawn, when used, to run quicker ; and that an increase 

 of temperature was necessary to excite the old, which he found as productive 

 as the new. When the bricks were formed, and while soft, he made holes and 

 inserted small pieces of spawn, which very soon impregnated the whole. He 

 did not think that Mr. Shearer, however anxious he might be to obtain 

 mushrooms, would succeed by raising the temperature to 70° ; he never allowed 

 fire heat to raise his house above 50° or 55°. He was opposed to the admission 

 of light, which he is sure is injurious to the mushroom. 



Mr. Thomas Keane agreed with Mr. Massey in the advantage of excluding 

 the light, and also with Mr. Grover in the benefit derived from syringing. 



Mr. Stanley had preserved spawn for seven years, and was one season un- 

 successful in growing them, although the bed was made with the same materials 

 and attention as in other years. 



A general conversation then took place, and from the answers given to the 

 many enquiries made on the subject, the failure was attributed to a combina- 

 tion of circumstances which cannot always be controlled by the best practical 

 gardeners. 



Mr. W. Keane believed, from his practice, and which was generally cor- 

 roborated by the observations that were made by the members who preceded 

 him in the discussion, that mushrooms are best grown in places excluded 

 from the light, and then detailed the practice adopted by the growers in the 

 neighbourhood of Paris, who supplied the market during the whole year with 

 mushrooms grown in quarries, where the same beds served for many seasons, 

 with the addition of a little fresh dung mixed three or four inches deep, to 

 enliven the bed for the spawn the better to work. He also agreed with the 

 opinions so generally expressed, of the advantages of gentle syringings to 

 create a dew, which, by its genial influence, is certain to increase the supply. 



Mr. Shearer, in his reply, entered at length into a full explanation of all his 

 practices, as detailed in his paper. 



Art. VI. Retrospective Criticism. 



Moistening the Air of Hot-houses hy Steam. — In p. 189. I find an article 

 on " Moistening the Air of Hot-houses," by T. Appleby, dated February 15. 

 1840, in which he states that he had admitted steam into the orchide- 

 ous house for nearly two months. If so, he must have commenced its 

 admission about the middle of December, at which period I should have 

 thought such treatment would have been injurious to the plants, as tend- 

 ing to force or excite them too prematurely. In this, however, I may be 

 wrong ; but I never admit the steam, much moisture, or increase the heat in 

 the house beyond 65° or 70°, until the beginning or middle of February, 

 according to the state of the weather j I merely mention this circumstance, as 



