280 REPORTS OF SOCIETIES. Dec., 1891 . 
OXFORD NATURAL HISTORY SOCIETY. — November 
3rd. A lecture was given by Dr. Collier on “ Stiffness, Fatigue, 
Breathlessness : What they are and what they mean.” The lecturer 
first described the mechanism and functions of the respiratory organs. 
As most people knew, the air when it entered the lungs gave up some 
of its oxygen and took out with it a larger proportion of carbonic acid 
gas than it had when it entered. The explanation of it was that the 
oxygen of the air absorbed in the blood united with the carbon of the 
tissues to form carbonic acid gas with the elimination of heat. 
Violent exercise increases the production of carbonic acid gas, and 
consequently also the number of the respirations to supply more 
oxygen and to throw off the carbonic acid gas. To many it was, no 
doubt, curious that a man was much more exhausted after ascending 
a steep hill of, say, 200ft. high than after lifting a very heavy weight, 
but the explanation was very simple. In the first case the man was 
demanding of his muscles, and a large number of them too, the work 
required to lift himself—probably from ten to twelve stone in weight— 
through a vertical height of 200ft., while in the second case he only 
demanded of a small number of muscles the work required to lift a 
hundred weight or two through a very few feet. When a muscle, or a 
set of muscles, were used these did not work alone, but another set 
immediately began to work in opposition, and it was this opposition 
which controlled and governed the action of the muscles used. This 
was one of the reasons why young animals, colts, lambs, &c., made 
such grotesque attempts to use their limbs at first—the muscles had 
not yet learnt to act together. Stiffness was the bruising and rupture 
of the muscle fibres by sudden and violent exercise. The best 
remedies for it were bot baths, friction, and moderate exercise. 
Gradually increasing exercise strengthened the heart greatly, but 
violent exercise in an untrained state did incalculable barm, producing 
dilatation of the heart and the thinning of its walls. At the close of 
the lecture, Mr. G. C. Druce exhibited specimens of the following 
plants :—lllecebrum verticillatum , L., from Berkshire (collected by Mr. 
A. Fisher) ; Sagina maritima (Don) var. alpina (Don), from Scotland 
(G. C Druce) ; Anchusa officinalis, L., Berkshire (G. C. Druce). The 
Sagina has not been found since 1800, when it was first discovered by 
Geo. Don on Ben Nevis.—November 19th. Lecture by Professor L. H. 
Vines, on “ The Disappearance of Starch from Leaves. ” The lecturer 
explained the way starch is formed in leaves and plants, and remarked 
that it is very easy to convert starch into sugar, but that the conversion 
of sugar into starch can only be performed by the plants themselves. 
He illustrated the lecture by some experiments, showing how ferment 
found in the salivary glands of animals converts starch into sugar. In 
malting, a ferment similar to that foundintlie salivary glandis extracted 
from the barley, called diastase. This diastatic ferment is present 
whenever starch is converted into sugar. As sugar can be detected in 
leaves which have been kept in the dark, it is thought that the ferment 
is present in the leaves, as in the seed. The lecturer exhibited two 
leaves from a castor oil plant, one of which had been put into boiling 
water immediately to kill it, and then into spirits of wine to bleach it; 
and the other, after being kept for twenty-four hours, was treated in 
the same way. The first leaf turned blue black, after being treated 
with iodine, thus showing the presence of starch; the second leaf 
remained uncoloured. If leaves are placed in chloroform for several 
hours the conversion of starch into sugar still takes place. An 
interesting discussion followed, in which the President, Mr. G. C. 
Druce, and Mr. Peters took part. 
