NATURAL HISTORY — BOTANY. 237 



He then showed that all experiments recorded on the growth of 

 Mummy Wheat were fallacious, and especially noticed the case 

 which had been relied on so much, of the growth of mummy 

 wheat by the Rev. Mr. Tupper, from seeds supplied him by Sir 

 Gardner Wilkinson. The mummy wheat in this case was known to 

 have been removed in jars that had been used for storing recent 

 wheat. He then alluded to the raspberry seeds from the stomach of 

 a warrior, found in the neighbourhood of Corfe Castie, and stated 

 that the old seeds were actually exhibited at the Horticultural 

 Society on the same table with recent ones, so that they might 

 easily have been mixed. A discussion ensued, in which numerous 

 cases of the supposed antiquity of seeds were given, but no case 

 which could be said to aiford experimental proof. 



EFFECTS OF NARCOTIC AND IRRITANT GASES ON PLANTS. 



Mr. John Livingston, in his paper which gained the prize in 

 the Botanical Class of the University of Edinburgh, after detailing 

 several experiments on Plants with sulphurous acid, hydrochloric 

 acid, chlorine, sulphuretted hydrogen, ammonia, nitrous oxide, car- 

 bonic oxide, and coal gas, remarks, — " It will be evident from the 

 preceding experiments, that gases divide themselves into two classes 

 as regards their action on plants — viz., into Narcotic and Irritant 

 Gases. This distinction, to whatever cause traceable, is as real in 

 the case of plants as in that of animals. When subjected to the 

 influence of a narcotic gas, the colour, it was observed, never be- 

 came altered, and the plants looked as green and succulent at the 

 end of the experiment as at the beginning. Whenever the plant 

 began to droop, though removed to a forcing-bed and watered, in 

 no instance did it recover, but died down even more speedily than 

 it would have done if left to the continued action of the gas. In 

 one word, narcotic gases destroy the life of the plant. With irri- 

 tant gases, on the other hand, the action is more of a local character. 

 The tips of the leaves first begin to be altered in colour, and the 

 discoloration rapidly spreads over the whole leaf, and, if continued 

 long enough, over the whole plant ; but if removed before the stem has 

 been attacked by the gas, the plants always recover, with, however, the 

 loss of their leaves. In a short time they put out a new crop, and 

 seem in no way permanently injured ; but, of course, if repeatedly sub- 

 jected to an atmosphere of irritant gas, the plants were destroyed." 



