Gelehrte Gesellschaften. 93 



to learn whether ,sclerotiets' are found in them also , and the con- 

 ditions und er which they occur. 



Mr. Stepheu Wilson writes: 



I have critically examined nearly a hundred of these bodies, and 

 have Seen nothing to suggest the inference that the lime is in the 

 interior of the ball. I have ruu in iodine, as Mr. Murray has done, 

 and its contact with the body reveals nothing whatever which is not 

 equally well seen without it. But the lime being iu the condition of 

 crystals, necessarily presents a rugged outline. Wbere the crystals 

 are not seen superposed , they are partly translucent , and this trans- 

 lucency, aloiig with the rugged outliues, presents a border which is 

 optically clearer than the more opaque interior of the field , aud this 

 clearer border has somewhat the appearance of plasm. But when the 

 process of Solution is watolied closely, the points of the crystals and 

 the outer crystals themselves, are seen dissolving, before the ,clear 

 definite outline' of the plasitaoidal body emerges from the eclipse. 

 The lime is seen beyond tbe ,clear definite outline', but the ,clear 

 definite outline' is not seen beyond the lime. The definite outline is 

 seen without any reagent after solutiqp of the lime; and if it is out- 

 side the lime it should be equally seen before Solution, without iodine 

 or any other reagent, which it certainly is not. 



The measures given in my first paper show that the lime ball 

 is larger than the plasmoidal ball. 



By focussing with a high power, while the crystals are dissol- 

 ving, it is seen that tlie vanishing fiagments in the centre of the 

 field are nearer to the eye than the optical edges of the definite out- 

 line, and therefore upon the outside of the ball. Mr. Smith and I 

 have given independent drawings exactly corresponding (Gardeners' 

 Chronicle, December 13, 1884, p. 757). Has Mr. Murray given any? 



Mr. Murray makes the inference that the plasmoidal ball is 

 ,the remains of the original cell-contents of the Potato leaf in which 

 the Oxalate of lime body was formed, adhering to it over the surface'. 



These bodies are not formed in the cells of the Potato leaf, but 

 lie in the intercellular passages , through which their mycelium runs 

 on germination, Others have called these bodies protoplasm , but my 

 owu observcitions seem to me to justify the inference that they consist 

 of fungoid plasm and short lines of mycelium. I have seen some of 

 these lines extending nearly a fourth part across the ball. Then Mr. 

 Murray wants to take the conceit out of me as to priority of dis- 

 covery. He quotes Dean Buckland, as asking Robert Brown regar- 

 ding certain Potato leaves , whether the ,aflFection' they showed was 

 that of the Potato disease. I have always contended that these para- 

 sitic balls were to be found in the undiseased tissues, where they lie 

 in a State of incubation. Along with the host plant they furnish a 

 good example of symbiosis. Now , if Robert Brown referred to 

 these bodies at all , he suspected that they were foreign to the real 

 tissues of the plant, and in some way connected with the Potato 

 disease. And if he did not refer to them , where is the relevancy of 

 this reference ? That Mr. Murray has found these bodies in ancient 

 Potato plants from the herbarium of Sir Hans Sloane was what I 



