Sexual Organs of Phytophthora erythroseptica , Pethyb . 121 
say ten centimetres long by four wide, which was kept permanently with 
the shell-vial containing the material, and on the slip was noted the length 
of time every reagent was allowed to act. When the material was 
embedded the slips were pasted into the notes in proper order. This 
method has several advantages. One knows at a glance how long the 
material has been in any particular fluid and the risk of leaving it too long 
is reduced. The transfer from one reagent to another may be noted as 
it is being made, and when the slips are preserved they provide an accurate 
account of the entire treatment which any particular lot of material has 
received. This is the only way in which mistakes in technique may be 
detected. Blocks of wood about two inches thick, with holes one and 
a half inches deep and about one-eighth of an inch larger in diameter than 
the diameter of the largest shell-vial used, are useful to hold the tissue 
while it is passing through the various reagents. 
Practically all material was cut at five microns thickness. It requires 
a very sharp knife to cut oospores without tearing them, and there is 
sometimes difficulty with them dropping out of their oogonia and off the 
slide. This may be obviated to a considerable extent by using a very 
dilute solution of gelatine in water, instead of plain water, to straighten 
the sections out on the slide, and then, when the excess liquid has been 
drained off and the slide is dry, putting it over a solution of formalin over¬ 
night. The very thin film of gelatine is thereby rendered insoluble and 
anything which was on the slide at the beginning is permanently fixed 
there. This treatment, along with which it is necessary to use albumen 
fixative in the usual way, is not generally necessary, however, particularly 
if the spores be thoroughly infiltrated and the knife sharp. 
Flemming’s triple stain gave by far the best results in staining, and 
it was used to the exclusion of all others, although many others were 
tried. It is particularly noticeable that Heidenhain’s iron-haematoxylin 
gave uniformly bad results. It was tried in three different laboratories 
at widely separated intervals of time, but in each case was an absolute 
failure. Very varied periods were used, from a few minutes in each fluid, 
as recommended by Kruger ( 22 ) and others, to twenty-four hours in each, 
but without success. Altering the concentrations was equally futile. 
Gentian violet alone or with orange G or other counterstain gave good 
results. Gram’s stain was also used with success. Flemming’s triple stain 
gave the best results with the following formula: Safranin, 1 per cent, 
solution in 50 per cent, alcohol (made up of equal parts of a 1 per cent, 
watery and a 1 per cent, alcoholic solution), 1 minute; water, a rinse; 
gentian violet, 1 per cent, solution in 10 per cent, alcohol, 5 minutes; 
water, a rinse ; orange G, 1 per cent, watery solution, about twenty seconds. 
The excess stain was wiped off and the slide-was dehydrated rapidly 
in absolute alcohol, followed by clove oil, and differentiated under the 
