Trow. — On Fertilization in the Saprolegnieae. 545 
ings before him, had a difficulty in interpreting the nuclear figures correctly, 
and readers of the paper have, at any rate in some cases, been led com- 
pletely astray. Davis (’03) and Hartog (’99) have even gone so far as 
to find in these imperfect conventional figures — separated, that is to say, 
by two removes from the actual facts — structures which the author of the 
paper was not able to see in the original preparations. An expert observer 
is always able to see more than he can reproduce in a figure, and every 
piece of original work must, therefore, be finally judged by the verdict 
of his fellow workers as based on collateral or confirmatory original observa- 
tions. If special reference to the illustrations which have been used as the 
vehicle to communicate the result to others is resorted to, it must be done 
with due caution. If the author has been simply unfortunate in his methods 
of presentation, the verdict in his favour may be delayed, but it will not be 
permanently withheld. But there is a real value in the criticism as to the 
want of detail in the drawings, in so far as that depends on the imperfection 
of the preparations themselves. The material used in both researches had 
been fixed by means of mercuric chloride. I am convinced that, so far as 
concerns the finer details of the structure of the nucleus, this method of 
fixation is quite unsatisfactory. Nevertheless the better methods used 
by me recently, and to be described hereafter, have not led to results in any 
sense contradictory of the earlier ones. The new results, indeed, confirm 
the old in every essential particular. Concerning De Bary’s influence much 
might be said if it were not already fairly well known. It is interesting, 
however, to contrast his mental attitude with that of Davis. De Bary (’87) 
says, referring to Pringsheim’s work : — ‘ If there is really an open com- 
munication in these species between the antheridium and oosphere . . . 
we must admit a fertilization in their case.’ Davis (’03) says, at p. 34 6 : — 
‘The writer cannot better sum up his attitude towards Trow’s opinions on 
sexuality in the Saprolegniales than by defining them as not proven and 
improbable in the face of the mass of observations upon which botanists 
have generally agreed that the group is apogamous,’ and again, at p. 236 : — 
‘ The writer cannot justify Trow’s conclusions in this matter, believing them 
to be premature as to evidence and illogical as to probabilities.’ One 
is tempted to ask what is meant by premature evidence and illogical 
probabilities. Further comment is needless. The greatest student of the 
Saprolegnieae, had he been able to pronounce judgement on the same facts, 
would, I imagine, have expressed himself differently and somewhat as 
follows: — If this remarkable succession in the number of the nuclei be 
confirmed, and there be no question of a nuclear division, we must at length 
admit that fertilization takes place in three species of Saprolegnieae — the 
view concerning the species destitute of antheridia, however, of course, 
remains unaltered. 
It must be admitted that the most difficult problem in the cytology of 
