333 
Marshall Ward . — On a lily -disease. 
Although I believe that the branching is due to the 
localisation of ferment-substance in the hyphae or segment, 
and that the nutritive medium may have an influence in 
directing a growing branch when once formed, it seems quite 
clear that this gives no explanation whatever of the remark- 
able phenomenon of the attraction which leads to the junctions 
between the hyphae ; and in the numerous cases, like those 
figured in Figs. 27-30, I cannot bring myself to believe that 
these factors alone determine the course and fusion of the 
hyphae. Moreover, I have convinced myself that mere 
contact between hyphae does not necessarily involve fusion, 
for in the case figured in Fig. 31 the upper hypha, having 
come accidentally in contact with the lower one, is seen to 
slide over in contact with the latter, without fusing with it at 
all, suggesting that one or both of the hyphae need to be in 
some special condition — I assume they must contain the 
ferment-substance in some necessary quantity or condition of 
action, or both — before they can conjugate. It is true that 
junctions are often established later in such cases as Fig. 31, 
at the point of contact where the two hyphae cross one 
another; but this only tends to prove the accuracy of the 
surmise that at the time of contact there was no attraction 
and no fusion, but that continued irritation at the point of 
accidental contact slowly causes a local accumulation of the 
ferment, and fusion eventually results at that point. It might 
be remarked that the case last quoted reminds one of the 
behaviour of some Myxamoebae prior to fusion into a plasmo- 
dium 1 ) for in this instance also we are compelled to assume 
that some remarkable state is necessary before fusion can 
occur. 
It remains to raise at least two more questions concerning 
this phenomenon In the first place, how is the attraction to 
be regarded? and in the second place, what object is served 
by the conjugation ? To these questions I can give no definite 
1 See Marshall Ward, An Aquatic Myxomycete, in Studies from the Biol, Lab. of 
the Owens College, vol. i, 1886, PL III and IV, pp. 64-85. 
