EDEMA 169 



Eppinger, while convinced that the beneficial results of thyroid extract 

 are due to its effect on cell metabolism, does not conclude that these cases 

 represent an atypical form of myxedema, but believes that the therapeutic 

 results suggest an association between hypothyroidism and edema. He 

 regards functional hypothyroidism, due to passive congestion, as a possible 

 explanation in a certain proportion of the cases. The histological inves- 

 tigation of the thyroid gland to ascertain whether associated anatomical 

 changes take place, was without result. 



Capillary Permeability and Edema. The normal permeability of the 

 capillary walls for certain substances is known to be very great, in that 

 these substances pass through freely and rapidly in either direction. Mag- 

 nus showed that by injecting hypotonic, hypertonic, and isotonic salt solu- 

 tions intravenously, salts, water, and albumin could be made to pass in 

 either direction through the capillary walls. 



Klicowicz also showed that such salt as sodium sulphate or sodium 

 phosphate, although foreign to the usual metabolic processes, would pass 

 through the capillary walls as readily as sodium chlorid. 



Modrakoski and Halter, working in Falta's clinic (referred to by 

 Falta and Quittner), have shown that by injecting small doses of the in- 

 fundibular portion of the hypophysis they can produce a marked diminu- 

 tion of the protein concentration of the venous blood, together with an in- 

 crease in the chlorid content, the total molecular concentration remaining 

 unchanged. These changes result apparently from the transfer of tissue 

 fluids to the blood. A normal status returned within a few hours. On 

 the other hand, adrenalin increased the concentration of red blood cells and 

 hemoglobin, without change in the salt concentration. In both cases the 

 capillary walls must be regarded as. quite permeable for water and for cer- 

 tain substances which pass in either direction as conditions demand. 



It is also known that after an intravenous injection of large amounts 

 of sugar, osmotic equilibrium is regained within half a minute after the 

 termination of the injection (Starling(a)), by the transfer of sugar to the 

 tissues. In a similar manner Van lyke and Meyer(&) have shown that 

 after injection amino acids disappear from the blood very rapidly and may 

 be recovered in the tissues. 



It can be demonstrated under the microscope that under local chemical, 

 mechanical, or thermal influences, the passage of certain constituents of 

 the blood through the capillary walls is increased. This transfer is seen in 

 local edema, due to inflammation or to the toxic action of iodin or of 

 quinin. In such cases, on the other hand, the rate of passage of tissue 

 fluidc into the capillaries seems to be diminished. 



Other evidence of increased permeability of the capillaries is based 

 on the more rapid disappearance of substances from the blood, or on the 

 occurrence of edema, after the administration of toxic substances. Magnus 



