156 
P. C. VAN DER WOLK, 
in fig. 2. The number of the ascospores is not fixed ; very many asci are 
only two-spored while on the other hand the greatest number of spores 
found per asci is fifteen. The fungus remains in this stage for a very 
long time. I therefore regard this stage as the normal condition of the 
full-grown mould. It is however noteworthy that in very old cultures 
there is a tendency for septa to form in the spores, so that we see here 
and there asci occuring with multicellular ascospores. Some of these are 
depicted in fig. 3. — I am inclined to regard the cell-multiplications as a 
degenerative phenomenon. We must however let this question rest aside. 
In the remaining figures I have represented various transitional stages; 
so fig. 4 represents the primary beginning of asci-forming. We see here, 
just as is distinctly shown in fig. 1, that these asci principally occur at 
the top of the mould-threads; and begin as small rounded or pear-shaped 
enlargements. The asci are therefore not sexually formed. In 
some cases they exhibit outgrowths, wich outgrowths continuate like ordi¬ 
nary mycelium threads, so that in older cultures the impression arises that 
the asci are also originated intercalliarly. On their development it is 
seen that these are not really intercalliary formations, and that originally 
all the asci are terminally disposed. In fig. 5 asci are represented with 
similar out-growths and quasi intercallary habitus. Fig. 6 gives a repre¬ 
sentation of the transition stage that leads up to the spore-forming. We 
see herefrom that septa may arise in different ways, through which the 
relative positions of the spores in different asci also produce differently; 
this may easily be observed in fig. 2. I have not been able to discover 
conidia. 
4. 
The mould was constantly cultivated at an ordinary in-door tem¬ 
perature, i. e. on the average 26° C. Under such conditions it flourished 
well. When it was submitted to higher temperatures its development 
declined; I constantly obtained the best results when no increase of tem¬ 
perature was introduced. This prevailed also with the artificial infections, 
as well as with the actual rearing of the mould from the ‘‘yellow grains“ 
themselves. 
Very beautifully succeeded experiments I obtained by drying up 
gradually, by little aud little the infected rice, without the least increasing 
of temperature. On this way I obtained the most characteristic “yellow 
grains“. The experiments with higher temperatures never succeeded in 
so a striking degree. Gradually drying up of the infected rice is the 
real secret of the forming of “yellow grains“. 
Hereby the concept must fail that the yellow grains specially arise 
through brooding only. Yet this was indeed formerly assumed to be the 
case by practical observers. It is evident that “yellow grains“ can occur 
in brooding rice, yet the crucial point is that it cannot be so through a 
high brooding temperature, but that in the first place the rice was infected 
by the mould, and in second place by the damp conditions favourable to 
the mould. The condition of humidity is in fact the cardinal point of the 
whole question. The absolute condition requisite for pigment forming 
is a very slight degree of humidity. Amid damp surroundings, 
wherein other moulds thrive luxuriantly, and produce an abundance of 
pigment, it is noteworthy that the pigment forming of Protascus is not 
at its optimum. Many of my experiments yielded no results owing to my 
