82 
Cayley . — Some Observations on the Life-history of 
Some of the material, especially that on bark, was dehydrated in 
glycerine and some in alcohol, cleared in chloroform, embedded in 54 0 C. 
paraffin, and cut from 2 to 4 \k thick. The youngest stages were cut 2-3 \x. 
It was found necessary, except for very young material, to use 
Henneguy’s ( 22 ) gelatine-bichromate solution for mounting serial sections 
to prevent the sections washing off during the process of staining. The 
solution was prepared as follows : One gramme of gelatine was dissolved 
in 5,000 c.c. tap-water, to which a trace of bichromate of potash was added 
before use. The ribbons were placed on the slide, and the gelatine solution—- 
which had been previously warmed in the 54 0 C. paraffin bath — was pipetted 
on to the slide. In this way the ribbon expanded rapidly without melting. 
Sometimes it was found necessary to warm the slide also, with the ribbon 
still floating on the gelatine solution. The superfluous liquid was then 
poured off and the slide blotted very gently and placed on several layers 
of blotting-paper on the top of the paraffin bath, to dry in the light for at 
least four hours. The bichromate did not seem to interfere with the staining 
as long as watery stains were used. 
Hcidenhain’s iron-alum-haematoxylin gave by far the best results and 
was used throughout, counterstained with a saturated solution of lichtgrun 
or erythrosin in clove oil. 
Media-. 
Conidia and ascospores of N. galligena will germinate well on a number 
of artificial media in common use in the laboratory and will develop 
considerable mycelial growth, but it was some time before a medium was 
found on which the fungus would go through all the stages of its life- 
history. The development is slow, and it takes at least 6-8 weeks, mostly 
longer, before the perithecial stage appears. Hence a medium had to be 
devised which would not dry out during that period. Platings proved to 
be useless on account of this tendency to dry out. Platings were made and 
the colonies transferred to slopes, or spores from pure culture sown direct 
on potato, &c. 
The only media on which the fungus would develop perithecia were 
those which contained starch, or some derivative of starch, together with 
glycerine. . 
It is to Goethe ( 16 ) that we owe the observation that the starch 
disappears in the starch -containing cells of the cortex when attacked by 
Nectria . It was found that spores sown on potato only gave rise to 
excessive mycelial and sporodochial growth and reached the macrospore 
stage, but would develop no farther; whereas ascospores and conidia 
grown on potato -f- 1 per cent, glycerine gave rather less mycelial growth 
and developed perithecia within two months. 
