1883.1 Polydesmus complanatus. 393. 
The same authority adds — “ I frequently find diseased 
potatoes at the root of the most flourishing and healthy- 
looking shaws. As to the potatoes, I have seen very few of 
them pass into a state of moist corruption ; neither have I 
been struck with an offensive smell given out by the plants, 
which, however, counts for little, seeing the olfactory sense 
varies. The tubers affeCted are easily recognised by the 
dark spots on the skin. If this is scraped off the subjacent 
tissue is seen to be of a brown mottled colour, which per- 
meates more or less extensively the naturally white flesh of 
the potato. When extensively diseased the potato loses its 
natural smoothness and colour, and is converted into a dark, 
rough, heavy mass.” 
Although competent microscopists, by the plan of hanging 
up wetted sheets of paper and afterwards submitting them 
to the microscope, have conclusively proved that the air 
around us is full of all manner of floating spores, I would 
have willingly credited my correspondent’s assertion that 
the mysterious myriapod might be guilty of spreading the 
infection. However, putting the matter to test, and en- 
closing the said myriapod with a choice example of a Sussex 
kidney, I then discovered conclusively it would not touch it, 
and that its nature was to prefer decaying leaves, agreeably 
to the taste of its kind and the remark of Prof. Westwood, 
that “ the Myriapoda delight in decaying vegetables.” 
Afterwards I introduced a couple of earwigs on the scene, 
and these, indubitably the more mischievous of the two, 
soon riddled and fairly consumed the potato. 
But to return to the main point. It is evident that 
moisture is necessary to extend the evil of the potato 
disease, and consequently there is less fear of it when the 
summer is hot and dry than when the season is characterised 
by much moisture, and more particularly moisture accom- 
panied with warmth, when myriapods doubtless abound. It 
has also been observed that thunderstorms, with the usually 
concomitant rain, are sure to be followed by an active deve- 
lopment of disease among the potato plants. 
Though the potato was introduced into Lancashire from 
Virginia, in America, by Sir Walter Raleigh, about the year 
1586, the disease is stated to be quite a recent importation. 
The year 1846, that followed on its first invasion, was the 
worst year known : i860 was likewise a bad one ; and it was 
bad in Ireland from 1876 to 1879 : then last year it was 
said that the growers of potatoes were everywhere at their 
wit’s end. Certainly this spring potatoes in Surrey have 
been proverbially bad, and villanously “ dark, rough, and 
VOL, V. (THIRD SERIES). 2 D 
