Ward.-— Recent Researches on the Parasitism of Fungi. 27 
Klebahn and others upheld the same view, and indeed the former 
seems to have suggested the resemblance already. However, the details 
are now of the less importance since Eriksson (66 and 67) has practically 
admitted the validity of my proof. 
(6) Eriksson relies to a certain extent on the analogy alleged to exist 
between his mycoplasm and certain cases of intra-cellular parasites, such as 
Woronin’s Plasmodiophora (206), Viala and Sauvageau’s P seudocommis in 
Vines, & c. (188) and others, and claims resemblances between them to 
which I shall have to refer later on. 
Taking these six points one by one, I would point out : — 
(1) The rusting of winter-sown Wheat at an earlier period in spring 
than spring-sown Wheat may obviously be due to the former having been 
longer exposed to the few spores which have survived the winter : it takes 
time for the year’s crop to become epidemic, and we know how easy 
it is to overlook the first pustules of the season. 
Moreover, the undoubted differences of susceptibility and immunity 
of various races complicate this question : nor can we overlook the weight 
of the evidence summed up in the references on pp. 13 and 14. 
(2) The absence of the Barberry and other aecidial hosts is conceded 
in many cases, and would be a real difficulty if the uredospores were found 
to be so short-lived as has been assumed ; but the mere fact that such spores 
will keep their capacity for germination for from sixty-one to ninety-four 
days (see pp. 11 and 12), and the evidence that we do not yet know the limits, 
should make us cautious here, to say nothing of the fact that germinable 
spores of P. dispersa have been found all the year round. See also p. 14. 
(3) Here again the reply is partly the facts just referred to, and partly 
that we are only at the beginning of knowledge as to the transmissibility 
of spores from Twitch and other weed Grasses, either direct or by means 
of c bridging species.’ Moreover, the results given in Blomeyer (34), 
Rostrup (147), Plowright (132), Kuhn (101), Hitchcock and Carleton (85), 
and Bolley (30) are, so far as they apply, dead against Eriksson’s con- 
clusions: they all declare for the persistence of uredospores and their 
retention of the capacity of germination through the winter. 
(4) An analysis of Eriksson’s experiments in large glass cases and tubes 
in the open is not easy; but the tubes (d) of 1893, a poor rust year, 
showed the presence of Erysiphe on the plants. Does Eriksson deny that 
this Erysiphe reached his plants by means of spores ; or does he also 
intend us to assume an internal origin for that Fungus also? In the cases 
where he does get uredo he asks us to believe that it is due to mycoplasm ; 
but if Erysiphe spores reached his specimens, surely the uredospores may 
have done so. 
Again, in the tubes (f) of 1894-9, where, of thirty-five plants, seven 
were rusted, I find there was abundance of rust around the experiment. 
