To illustrate some of these small magnitudes I have adapted the preceding diagram from one given by Zsigmondy43. Upon the {40} same scale the minute ultramicroscopic particles of colloid gold would be represented by the finest dots which we could make visible to the naked eye upon the paper.
A bacillus of ordinary, typical size is, say, 1 ôç in length. The length (or height) of a man is about a million and three-quarter times as great, i.e. 1ôñ75 metres, or 1ôñ75ã₤ûã₤10ÿ£¢6 ôç; and the mass of the man is in the neighbourhood of five million, million, million (5ã₤ûã₤10ÿ£¢18) times greater than that of the bacillus. If we ask whether there may not exist organisms as much less than the bacillus as the bacillus is less than the dimensions of a man, it is very easy to see that this is quite impossible, for we are rapidly approaching a point where the question of molecular dimensions, and of the ultimate divisibility