Proceedings, 3 



and in some instances the fungus itself in a fossilised state 

 may be detected by the microscope. The disease in question 

 does not confine itself to the Potato, but readily spreads 

 amongst other members of the same natural order, the 

 SolanacecB, such as the Tomato, which has suffered quite as 

 much as the Potato, entire crops being often destroyed by 

 the blight. It also attacks, but less destructively, our wild 

 Solanea, as 8ola7ium Dulcamara, &c. In their tropical haunts 

 the SolanacecB, including both Potatoes and Tomatoes, which 

 are entirely exotic, have a hardier growth and a much 

 stronger constitution ; they consequently do not suffer so 

 severely from disease as they do in the somewhat unnatural 

 and artificial circumstances in which they find themselves 

 with us. Our indigenous Solaiiem, as Solaniim Dulcamara, 

 Hyoscyamiis niger, and Atropa Belladonna, are liable to be 

 affected by the fungus ; but, being hardy, they do not easily 

 take it, and when affected readily throw off its effects. When 

 Tomatoes are cultivated under glass, and maintained at a 

 temperature and under conditions generally resembling those 

 of their native habitats, they are not nearly so liable to 

 disease as when exposed in the open air. The height of the 

 fungus is often less than the thickness of the leaf on which it 

 grows. This fungus always accompanies the disease, and the 

 most competent authorities are agreed in considering it the 

 cause of the disease itself. Its ramifications or roots bore 

 their way into the substance of the leaf and other parts of 

 the plant, the sprays finding egress at the stomata or 

 breathing-holes on the surface. 



To Mr. Worthington Smith, more perhaps than to any- 

 one else, we owe the knowledge we now possess of this 

 extraordinary fungus. This gentleman was engaged in 

 examining the specimens sent to him, when suddenly he saw 

 displayed within the field of his microscope the same trans- 

 parent round bodies seen long before by Dr. Montague. 

 There could be no doubt that they were indeed the resting- 

 spores of the Potato-murrain, as they appeared in the tissues 

 of the leaf itself, and not on the surface where they had 

 hitherto been looked for ; and each had germinated and sent 



