AN EXPERIMENTAL ANALYSIS OF OEDEMA 27 



had previously been used for a number of experiments ex- 

 tending over a considerable period of time. It had there- 

 fore become extremely thin and weak at the time of this last 

 experiment. After injecting into the subcutaneous lymph 

 sinuses 1 cc. of a 0.975 per cent solution of NaCl, the writer 

 put the frog into tap-water at 26° C. Curve 6 in figure 1 

 shows us that, after a slight gain which was followed by a 

 considerable loss in weight, the frog began to gain weight 

 continuously. This gain was accompanied by red-leg symp- 

 toms which unexpectedly made their appearance some time 

 between the eighth and twelfth hours of the experiment. 



Having considered the general symptoms of red-leg disease 

 in frogs and the general behavior in water of frogs so afflicted, 

 let us now attempt to explain the presence of the oedema, 

 both localized and generalized, associated with this disease, 

 on the basis of those factors involved in the production of 

 oedema which we have outlined in the preceding pages. 



We may state that the presence in iiogs of a localized 

 oedema indicates the probability, at least, that the oedema 

 of this character is not due to inefficiency in kidney function. 

 As a matter of fact, an examination of the urine of frogs in 

 which the oedema is localized has shown that the oedema is 

 not always accompanied by albuminuria. Albuminuria is of 

 frequent occurrence in red-leg disease, however, when con- 

 gestion has become general. 



If, by the aid of a binocular microscope, we follow the prog- 

 ress of congestion in a case of red-leg in which at first the 

 web of the foot is alone congested, we meet with conditions 

 which we have the right to assume represent a typical clinical 

 picture of what may similarly occur elsewhere in the body 

 when congestion has become more general. The condition 

 which we actually observe in the foot is the establishment of 

 a localized mechanical block in the vascular system, predis- 

 posing to the establishment of a typical case of localized 

 subcutaneous oedema of exactly the same character as that 

 which would have been formed had the foot of the frog been 

 ligated. If we follow the progress of the disease as it spreads 



