Under laboratory conditions the mucilage is unattacked by the digestive enzymes, and even when fed to a non-ruminant animal 75 per cent. can be shown to pass through unchanged. As far as such a point can be demonstrated by laboratory experiments, it is however probable that the mucilage is attacked by intestinal bacteria, and, in ruminants especially, largely broken up in this way, with the evolution of gases and certain volatile acids among other products. This behaviour while unexpected at the beginning of the investigation is not inconsistent with its chemical character as a hydrated cellulose. A similar case is perhaps found in the substance agar-agar, which is readily attacked by bacteria, but is stated by Armstrong in his article on “Carbohydrates” in Allen's Organic Analysis to be practically indigestible by the human organism.

The following brief summary may be given on the aetiology of drought resistance as exemplified by the conditions obtaining in 1911.

From an agricultural point of view the value of a plant as a drought-resister is seen to be measurable by two standards: (1) Its power to give a good yield all through the period of drought; (2) its ability through living through the summer without materially adding bulk to the herbage to recuperate when the conditions become less severe. It has been shown that the phenomenon of drought-resistance is not associated with any one set of morphological characters, but that various growth forms are met with amongst the most successful plants. Further, a number of plants have shown themselves very tolerant, although having no apparent modifications to assist them, in which case there can be no doubt that their power of resistance is a simple outcome of their inherent vitality. Consequently it is perhaps dangerous to assign too great an importance to the possession of apparently useful modifications. A fair correlation is however seen to exist between a plant's manner of resistance and its growth form, as the following classification shows.

The conclusions reached in our previous paper have been confirmed and extended. Fresh evidence is adduced that bacteria are not the only inhabitants of the soil, but that another group of organisms occurs, detrimental to bacteria, multiplying more slowly under soil couditions and possessing lower power of resistance to heat and to antiseptics.

In consequence of the presence of these detrimental organisms the number of bacteria present in the soil at any time is not a simple function of the temperature, moisture content and other conditions of the soil. It may, indeed, show no sort of connection with them; thus rise of temperature is found to be ineffective in increasing the bacteria in the soil; increase in moisture content has also proved without action. The number of bacteria depends on the difference in activity of the bacteria and the detrimental organisms.

1. The numbers of bacteria and fungi in a newly-made Stilton may rise to the enormous number of 1000 to 3000 millions per gram in the first week.

2. There is a gradual fall in the numbers up to the time of ripeness (100 to 150 days old), when 50 to 100 millions only are found.

3. In the early stages lactic acid bacteria are most abundant. When the cheese is ripe the lactic acid bacteria are few and weakened in physiological power; Penicillium glaucum and a form of Torula are then abundant.

4. Five characteristic organisms are found in all Stilton cheeses examined, viz.:—(1) Streptococcus lacticus, (2) a short rod-shaped form of Bs. acidi lactici, (3) a species of Tyrothrix, (4) Penicillium glaucum, and (5) a round form of Torula, sometimes accompanied or replaced by an oval form.

In cheeses where starters have been used we find a large celled form of Streptococcus lacticus present.

5. Penicillium glaucum is checked in its growth by the Tyrothrix.