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the manner in which the fniit of this group of fungi is disseminated under 

 ordinary circumstances. The jet-like clouds of smoke are the result of the rupture 

 of a number of asci simultaneously. They occur only when the Peziza has attained 

 full maturity, the asci being, so to speak, in a state of tension, from their contents 

 having attained the maximum amount of development. Under such circumstances 

 the giving way and consequent emptying of one ascus, disturbs the equilibrium of 

 those in immediate contact with it, and as they are fully matured, the slight con- 

 cussion thus produced is a suflBcient exciting cause to render manifest the latent 

 elasticity of their walls ; the measure of which elasticity being determined by the 

 distance to which the cloud is expelled. 



On the 29th May, 1879, 1 gathered about one hundred specimens of Morchella 

 gigas, Pers., and laid them out separately upon boards in my study. In the even- 

 ing, as the rays of the setting sun fell obliquely upon them, I observed that all the 

 older specimens were quietly and continuously diffusing their sporidia. Each 

 sporidium was distinctly visible to the naked eye, floating in the air, twisting and 

 turning in the sunlight. The head of each of the morells in question was sur- 

 rounded by a cloud of sporidia extending three or four inches above and around it. 

 This cloud could only be seen in the oblique light against a dark background. 

 When acted upon by a gentle current of air, such as would be produced by gently 

 waving the hand, it swayed to and fro, without manifesting any tendency to 

 become dispersed. The component sporidia were in constant motion, rising and 

 falling, and circling about, as if the law of gravity were a myth, existing only in 

 the imagination of philosophers. When the cloud was blown quite away by a 

 more powerful air-current, it, in the course of a few seconds, re-formed. The 

 contents of each ascus could be seen to be separately ejected in a minute jet, con- 

 sisting of a limited number of sporidia, which speedily became lost with the others 

 forming the cloud. 



The phenomenon above described is interesting from a physiological point 

 of view, as showing the capabilities of the unaided human eye. These sporidia 

 measured only about one-hundredth of an inch in their long diameter, and iive-one- 

 thousandths of an inch in their short— yet they could distinctly be seen to be 

 bodies having length and breadth. 



That the process above described is the normal mode in which the sporidia 

 of the Morchellce are diffused, and not the result of an accidental chain of circum- 

 stances, is further shown in another way. A lady who has a particularly irritable 

 skin, and who has often accompanied me in my mycological excursions, was never 

 able to gather Morells without suffering from a very unpleasant erythema of the 

 face the explanation of which was never arrived at until the above observations 

 were made, although experience had taught her that the Morells must always 

 be kept at arm's length. 



What particularly struck me when observing these spores being given off, 

 was the facility with which they floated in the air, having little or no tendency to 



