28 Reviews. — Lindhifs Theory of Horliculture. 



raising young plants; in prevention of the growth of those 

 minute fungi, which cause entire crops to damp off; Chapter 

 III. may be perused with advantage. The succeeding chap- 

 ter on Ventilation sets the subject in a just light, and is, while 

 opposite to the older methods, perfectly in accordance with 

 the facts of modern science. Cooling down a green-house by 

 " giving air" from the top glasses, and rather creating a cur- 

 rent of wind through the house, always seemed to us rather a 

 harsh way of managing plants, especially in mid-winter. The 

 difference, however, between the natural solar heat of our 

 skies and those of England, should be taken into considera- 

 tion. Yet even then, in very many cases, we opine that par- 

 tial shading to modify the sun's rays, would be more condu- 

 cive than raw, cold air. Ventilation is sometimes very essen- 

 tial to remove those impurities arising from the use of sulphur 

 and other substances. To those who have suffered from an 

 improper use of sulphur for instance, it may be interesting to 

 learn, that according to Drs. Turner and Christison, one ten 

 thousandth of sulphurous acid gas, would destroy leaves in 

 forty-eight hours, and that similar effects were obtained from 

 hydro-cliloric or muriatic acid gas, chlorine, ammonia, and 

 other agents, the presence of which could not be ascertained 

 by the smell. From these, it may be gathered, that the man- 

 agement of the forcing-house and conservatory should be 

 conducted on careful data: and in no branch with more scru- 

 pulous attention, than in a proper ventilation. So far as the 

 natural atmosphere is concerned, plants will survive and grow 

 and thrive, in a perfectly confined area, as the beautiful ex- 

 periments of Mr. Ward, with his glazed, tight cases have 

 shown. This plan has even been carried to a great extent in 

 the formation of hot-houses, for the especial growth of tropical 

 plants. 



Chapter V., on seed saving, offers some remarkable facts. 

 To the success of the following, we can testify in our own 

 late experiments, having at this moment, several thrifty seed- 

 lings of the same species of plant, from seeds submitted to 

 the process of boiling for five, and even /or ten minutes. 



Flax seed will grow after a similar process; while the 

 scalding of ipomasa seed is recommended as promotive of 

 speedy vegetation. Among seeds of plants sent from China, 

 and most probably submitted to a baking process, or to some 

 such as generally destroy the germ, occasional instances of 



