402 REPORTS ON THE STATE OF SCIENCE. 
(b) All diuretics which have been used with the exception of urea in 
certain doses lead to increased kidney metabolism. 
In connection with the question of the metabolism of the frog’s 
kidney, determinations have been made of the urea percentage of the 
frog’s blood. For this purpose the blood from two to four pithed frogs has 
in any given sample been taken by bleeding into alcohol. Estimations of 
different samples show that the urea amount varies considerably, but the 
general result indicates a high percentage (0-06 to 0-1 per cent.). 
(2) The Intestine of the Dog.—A method of estimating the rate of 
blood-flow through an isolated loop of the intestine by means of the 
oncometer has been developed and a series of observations upon the 
gaseous exchange during rest has been made. Attempts to determine 
how far such gaseous exchanges are to be debited to mucous membrane 
and to muscle wall respectively have not at present yielded definite 
results. 
Experiments have been conducted in order to follow the gaseous 
exchange during the absorption of sodium chloride solutions of different 
strength ; all such experiments have shown a distinct increase both in 
oxygen intake and in carbonic acid output ; the rate of absorption of the 
Cl and of the water has been followed. 
In a third series of experiments the gaseous exchange during the 
absorption of a solution of Witte’s peptone was determined. 
(3) The Mammalian Heart.—Two series of experiments have been in 
progress as to the metabolism of the heart: (a) those in which it was 
perfused with blood, (4) those in which it was perfused with saline 
solution. In the first series a number of the experiments were made 
when the oxygen tension in the lungs was reduced either by partial 
obstruction of respiration or by an atmosphere containing only small 
quantities of oxygen. It was found that as the arterial blood gets 
darker the flow through the coronary vessels of the supplied heart 
increases ; at the same time the heart-beat slows and appears to become 
less efficient. In the second series it was found that with the rabbit’s 
heart perfusion with saline solution at 35° C. is associated with a gaseous 
exchange of the same order as that found on perfusion with blood (0°02- 
0:01 c.c. of oxygen intake per gramme per minute). The effect of altering 
the amount of dextrose in the saline solution is now being studied. 
(4) The Submawillary Glands.—A fresh series of researches has been 
started upon the gaseous metabolism of the submaxillary glands of the 
cat, with the object of ascertaining the effect produced by the stimulation 
of the sympathetic, and of thus determining more precisely the relation 
between cell metabolism and blood-flow. Among the results obtained are 
positive indications that dilatation of the gland vessels can be produced 
in consequence of changes which occur in the gland cells. The output of 
CO, as one phase of the whole metabolism is apparently diminished by 
sympathetic stimulation, whilst the other phase, intake of oxygen, appears 
to be unaltered or only slightly altered. It is not certain how far the 
apparent diminution of CO, may be accounted for by changes in alkalinity 
of the gland. 
Technique.—Apart from the special technique required in the fore- 
going experiments, some general aspects of technique have been studied 
by means of definite series of experiments. Among these are the 
following :— 
