jo Ward. — Recent Researches on the Parasitism of Fungi. 
In fine, no trace of the alleged mycoplasm can be discovered, and 
all the facts point to the necessity of a thorough revision of the hypothesis 
in the light of comparison with the normal course of infection, and with 
what we now know of the behaviour of the spores. 
Eriksson claims that the mycoplasm hypothesis is ‘ proved, at least 
until sufficiently comprehensive proofs to the contrary have been produced 
from some other quarter/ But this kind of argument cannot be accepted : 
the onus of proof is with him. I think that if the infecting spores are 
sought for, by means of serial sections through the flecks which yield 
the ‘ protomycelium ’ and ‘ mycoplasm ’ at their edges, they may be found, 
because we often find the entry even on the eighth or ninth day after 
inoculation, and are generally able to detect the place of entry of the germ- 
tube in pustules on Wheat in the open. Until this is done, I can only 
maintain that the mycoplasm hypothesis depends on the reading back- 
wards of the course of events, on the part of an able and eminent 
observer, for whose work in other departments, and especially in the field, 
we must all have the greatest respect. 
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17. (’79) : Ueber die Erscheinung der Symbiose. Strassburg. 
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