A CHAPTER IN THE PHYSICAL GEOGRAPHY OF THE PAST. 59 
That there are some of you here, to-night, who are specially 
interested in bacteriology, must be my excuse for referring some- 
what at length to this interesting fact which, as far as I know, has 
not yet found its way into text-books. 
In the year 1879 Van Tieghem announced to the French 
Academy of Sciences that he had discovered in certain micro- 
scopic sections of plants from the Coal Measures of Saint Etienne, 
undoubted traces of a minute organism well-known to bacteriolo- 
gists as Bacillus Amylobacter. This Bacillus is very active in the 
destruction of the cellulose of vegetable tissue, and is identical 
with Pasteur’s butyric acid ferment. So we see that in the 
marshes of the Coal Period plants underwent decomposition by 
identically the same agent as they do at the present day, and that 
even at this very remote time, probably separated from our day by 
millions of years, this daci//us was at work partially destroying the 
dead tissues of the higher plants, and facilitating their conversion 
into coal for our use. This is the only well authenticated case, as 
far as I know, of the discovery of a fossil bacterium,* and it is 
a suggestive fact that, whilst in course of untold ages its con- 
temporaries high up in the scale of existence have undergone 
enormous change, this lowly organism is to-day both morphologi- 
cally and functionally what it was in the Coal Period 
In order that you may picture to yourselves the relation of land 
and water in the British Islands during the Coal Period, I must 
refer you once more to the map of Lower Carboniferous times. 
You must imagine that all the area marked as sea has been con- 
verted into very shallow water or swampy ground, and that these 
lagoons have somewhat encroached upon the old shore lines, thus 
reducing the area delineated as land on the map. The great 
Central Island still existed, but it was narrowed somewhat, and 
perhaps also split up into a chain of two or three islands. The 
Southern Uplands of Scotland, which stood above the water in 
Lower Carboniferous times, were now submerged, and the island 
of the Lake District became much smaller. Still on the whole the 
* Béchamp’s observations on his supposed fossil microzyme of the chalk 
—Microzyma cretce—have been found to be erroneous. 
