Table 1.

Calculated number of particles of molecular weight 230 000 expected in 4000 × 4000 Å square image area for a specimen thickness of 300 Å, provided depletion or surface adsorption is prevented

Catalase protein concentration (mg/ml)	Number of particles expected in images of a 4000 × 4000 Å area, 300 Å thick
0.1	1
0.2	3
0.5	8
1	15
2	30
5	60
10	125
20	250
40	500