14 
a new series of contractions, simply by washing it. Of course we 
do not wash the outer surface, but having found the artery which 
carries the blood to the muscle, we pass through it water, instead 
of blood. But not pure water, which acts most injuriously on all 
the cells of an organism,—a fact which it is well to remember 
when one has to wash deep wounds. The muscle would swell up 
and die if pure water were introduced into the circulation instead 
of blood ; hence a little table salt is added to the water (7 grams 
to a litre, or in English measure, 60 grains to a pint), and this 
solution closely resembles blood serum. Upon the passage of a 
current of this liquid through the muscle the fatigue disappears, 
and the contractibility returns and is as vigorous as at the 
beginning. A similar result may be arrived at by massage. It is 
well known that a hot bath, followed by vigorous massage, will go 
far to remove the feelings of muscular exhaustion following any 
very arduous work. The chief products that are removed by 
washing the muscle separated from the body, or by massage of the 
muscle attached to the body are:—Carbonic Acid and _ Lactic 
Acid, ane certain ptomaines which make the blood of a fatigued 
animal tonic to another animal. 
Other physiologists, especially Professor Herter of New York, 
and Professor Lee of Columbia University, have approached the 
subject from another standpoint. Their explanation of the 
symptoms of fatigue is: that it is caused, not so much by what is 
formed in the muscles, viz,.Lactic Acid, Carbonic Acid and 
Ptomaines, as by that which is lost from the muscular fibres. You 
will find the subject discussed in Professor Herter’s ‘‘ Chemical 
Pathology.” His conclusion : Is that it is loss of sugar from the 
muscle which is the chief cause of fatigue. It seemed to Professor 
Lee that if this were so, then by depriving the muscles of their 
muscle sugar, or more correctly glycogen, or muscle starch, then 
fatigue ought to show itself. In Phlerhizin we have a drug which 
has the singular property of impairing the combustion of sugar, 
and of permitting its escape in the urine, thus depriving the cells 
of the muscle of their supply of sugar. It was found that animals 
subjected to the action of this drug for several days rapidly 
became fatigued, and their leg muscles only gave 200 to 400 
contractions per minute, instead of the normal 800 to 1,000, on 
electrical stimulation. This is the explanation of the rapid way 
fatigue comes on in Diabetes. I have given you the two chief 
theories. I have no doubt there is truth in both explanations, 
and the probability is that muscular fatigue is a much more 
complex state than we as yet suspect. However, much good has 
been done by the discovery that fatigue means diminution of 
muscle sugar, and it furnishes you with a scientific excuse for 
taking some chocolate, or other sweetmeat, with you when taking 
a long walk. In connection with muscular fatigue I ought to 
. 
