20 THE RESTINO-SPOP.ES OP THE POTATO DISEASE. 



Reference should here be made to the bodies found germinating 

 in the intercellular passages of spent potatos by Dr. Montague 

 (Artotrogus), and referred by Mr. Berkeley to the Sepedoniei. 

 Ever since Mr. Berkeley first saw these bodies he has had an un- 

 swerving faith in the probability of their being the secondary form 

 of fruit oi Feronospora injcstans, but unfortunately, as far as I know, 

 no one has ever found a specimen of Artotrogus since Montague. 



The question may, therefore, be naturally asked, in conclusion 

 — How does Artotrogus agree with the presumed resting spores 

 here figured and described ? And has Mr. Berkeley been right or 

 wrong in clinging so tenaciously to his first idea? Fortunately for 

 the investigation of the potato disease (which can never be cured 

 till it is understood), Mr. Berkeley has given in the " Journal of 

 the Royal Horticultural Society " the number of diameters his 

 figures are magnified to, and I have here further enlarged those 

 figures so as to correspond in scale with my own drawings, which 

 latter are sketched with a camera lucida. It will be seen that they 

 are the same with each other both in size and habit, with the ex- 

 ception of the processes on the mature spore of Artotrogus — which 

 processes may possibly be mere mycelial threads, or due to the col- 

 lapsing of the inflated epispore. The reason these resting-spores 

 have evaded previous search is that no one has thought of finding 

 them amongst leaves which had been macerated for a long period 

 in waert. There is, however, nothing unreasonable in fruit being 

 perfected in water or very damp places, as it is common in the 

 Saprolegniea? and amongst Alg£e in general. To sum up, there 

 are four reasons why the bodies here described bSlong to the old 

 potato disease : — 



1. Because they are found associated with the Peronospora and 

 upon the potato plant itself. 



2. Because they agree in size and character with the known 

 resting-spores of other species of Peronospora. 



3. Because some other moulds are aquatic in one stage of their 

 existence. 



4. Because they agree in size with Artotrogus. 



I will only say in conclusion that it affords me great pleasure to 

 lay these additional notes on the potato disease before the Society 

 which thirty years ago published Mr. Berkeley's original and excel- 

 lent memoir on the same subject. — Gardener'' s Chronicle, July 10, 

 1875. 



N.B. — Mr. W. G. Smith has also published in the succeeding 

 numbers of the same Journal, July 17th and July 24th, further 

 particulars and details of this subject with illustrations, to which 

 we must refer our readers, as confirming and extending the obser- 

 vations above recorded. — Ed. Grev. 



