142 
DR. P. F. FRANKLAND ON THE QUANTITATIVE ESTIMATION OF 
Rate. — 2 - 5 strokes per minute. 
, . . f. f25 moulds. 
(Jotomes in flask, 39 j ^ ^ 
Control tube, containing plug of sugared glass-wool and sugar-powder, 
exposed the whole time occupied by No. 1. 
Colonies in flask, 0. 
12 litres of air yielded, therefore, 22 colonies. 
No. 2. Hesse’s method. 
Time. — 6.20 p.m. to 7.15 p.m. 
Volume of air =12 litres. 
Tube contained 32 colonies 
19 moulds. 
1 licp 
Control-tube contained 16 colonies 
5 moulds. 
1 liq. 
IIT. Chemical Laboratory. October 15, 1886. Shortly after students had left. 
4.50 p.m. to 5.32 p.m. 16°-9 C. 
Nos. 1 and 2. Flask method. —(Double plugs.) 
No. 3. Hesse’s method. 
Nos. 1 and 2 were alternated in aspiration. No. 3 simultaneously aspirated 
in close proximity, the tubes being inclined at the same angle. 
No. 1. Volume of air = 24 litres. 
Construction of plugs. — (a) Glass-wool only. 
(b) Sugared glass-wool and sugar-powder. 
Rate. —8 strokes per minute. (Tube exposed 12 minutes.) 
,-y 7 . . n i / X ^ f 40 moulds. 
Colonies in flasks. — (a) 73 j 
( b) 1 mould. 
No. 2. Volume of air =18 litres 
Construction of plugs. — (a) Sugared glass-wool. 
(/>) Sugared glass-wool and sugar-powder. 
Rate. —7'3 strokes per minute. (Tube exposed 9 minutes.) 
23 moulds. 
0 liq. 
(b) 2 moulds. 
Colonies in flasks. — (a) 43 
Control-tube, containing plug of sugared glass-wool only, exposed 46 minutes. 
Colonies in flask, 0. 
10 litres of air yielded, therefore, in 
jNo. 1 (glass-wool), 31 colonies. 
[No. 2 (sugar-wool), 25 „ 
