20 INTERNAL SECRETION 



In the larger number of cases, experimental extirpation does not 

 yield reliable results, unless these are supplemented by experimental 

 substitution. This method offers the best means of combating 

 the old argument, that the symptoms of suppression which follow 

 the extirpation of an organ are really due to unavoidable secondary 

 injuries. But if after transplantation where the normal nerve 

 connections are severed and the local conditions changed there are 

 no pathological symptoms, while these appear as soon as the 

 transplanted organ is extirpated, then it is obvious that the cor- 

 relative activity of the organ in question is not nervous in its 

 origin, nor dependent upon an external secretory function, but 

 is wholly chemical and internal secretory in its nature. Clinically 

 successful transplantation, whereby a threatening pathological 

 condition has been averted or a declared one cured, would com- 

 plete the chain of evidence. Nor is such confirmation lacking. 

 The testicle, ovary, thyroid, suprarenals, &c., have all been 

 transplanted with good result. It must be remembered, however, 

 that, even where transplantation is apparently successful, the 

 supply of blood and of nutrition may, under the new conditions, 

 prove insufficient and the organ may eventually cease to function. 



The discovery that the implantation of an organ which does 

 not successfully heal in, may yet temporarily replace the sup- 

 pressed function, pointed the way to a simpler method of 

 substitution, namely, that known as organo-therapy, or the 

 Brown-Sequard method. This method is founded upon the 

 assumption that the internal secretion elaborated by an organ 

 is contained in the tissue of that organ and, more particularly, in 

 the juice expressed therefrom. It was thought that, even though 

 the actual amount of active substance present in the organ must 

 necessarily be small, yet, in view of the extreme activity of the 

 extract, it must be possible to obtain all the effects of substitution, 

 especially if the administration was continued over a long period 

 of time. The brilliant results of organo-therapy in the patho- 

 logical conditions due to suppression of the thyroid, amply prove 

 the justice of this theory. Similar results, though by no means 

 so striking, have been obtained in connection with other organs ; 

 while in the case of yet others, the extract of the organ in question, 

 whether given by the mouth or by subcutaneous, intraperitoneal, 

 or intravenous injection, produced but unimportant and, in some 

 instances, barely perceptible, effects. The organic extract and 

 expressed juices depend for their effects, not only upon the 

 method of their preparation and employment, but also upon 

 certain other conditions, of undoubted importance, but of which 

 little is at present known. For reasons which have already been 

 discussed, the failure of organo-therapy in any given instance is 

 not to be regarded as evidence against the existence of an internal 

 secretory function of the organ in question. 



Quite apart, however, from their substitutive effects, the 



