So 6 Stoward.—A myloclostic Secretory Capacities of the 
Brown and Escombe respectively, secrete a cytoclastic enzyme, and also 
to study the mode of attack on starch grains of the amyloclastic enzymes 
which these tissues secrete. 
The data derived from these variously conducted experiments and 
their discussion are embodied in the separate sections which follow. 
II. Culture Media and Substrata. 
Variously constituted culture media and cultural conditions have, during 
the course of the inquiry, been employed. 
Reference need only be made at this juncture to the composition of the 
medium which has served as the basis of those used in the majority of the 
culture experiments to be described. Wherever modification of its composi¬ 
tion, either by the inclusion of other substances or change of concentration 
of a particular component, has been made, attention is directed to the fact. 
The composition of the medium shortly referred to in this paper as the 
‘ mineral salt solution or more briefly, as ‘ M.S. solution’, is the following:— 
Per ioo c.c. of solution. 1 
Calcium sulphate o-ioo grm. 
Potassium chloride 0*25 
Magnesium sulphate 0-25 
Potassium dihydrogen phosphate 0*025 
2 drops of N/5 Fe 2 Cl 6 per litre of solution. 
Method of investigating material and culture media for amylase. At the 
termination of the culture experiment the objects and corresponding culture 
medium from a given plate culture were separately investigated for amylase 
by digestion with soluble starch under definite and comparable conditions 
of time, temperature, and concentration of starch solution. 
These digestions were carried out in the following uniform manner:— 
Into each of a series of 50 c.c. conical Jena flasks, previously cleaned by 
steaming them out, 25-30 c.c. of freshly prepared soluble starch contain¬ 
ing 3 grm. starch solids per 100 c.c. of solution were pipetted. The flasks 
and their contents with the addition of a drop of antiseptic (nitrobenzene or 
toluene) were at once transferred to a thermostat regulated at 30° C. 2 
Those required for the control starch digestions, before addition of the 
enzyme-containing material, were rendered distinctly, but not excessively, 
alkaline by the addition of a few drops of 30 %~4o % NaOH solution. 
The objects, previously desiccated for some hours (5-2°) at 30° C, were 
divided into two portions, each consisting of an equal number and represent¬ 
ing one-half the total number on the plate, were separately and uniformly 
1 Trans, of Guinness Research Lab., vol. i, Part II, p. 290, Brown, Millar, McMullen, and 
Escombe. 
2 Unless otherwise stated, it is to be understood that all starch digestions referred to in the text 
were carried out at this temperature ; the temperature of the thermostat never varied throughout by 
more than + or — 0-5° C. 
