Ageing of Elastic Tissue 103 



purified elastin. In micro-incinerated preparations the calcium 

 in elastic fibres may be recognized as very heavy deposits of 

 a brilliant white ash when the specimen is viewed with dark- 

 field. We have made micro-incinerated sections of a number 

 of specimens of skin exhibiting senile elastosis; to date we have 

 found no evidence of a tendency toward mineralization of the 

 elastic fibres in this lesion. 



There has been some question as to the nature of the fibres 

 found in senile elastosis; all of the evidence found in our 

 laboratory would establish that the fibres are elastic. They 

 stain typically with the usual stains for elastic tissue, resorcin- 

 fuchsin, orcein, and the Verhoeff reagent. Thin sections of 

 osmic acid-fixed fibres of normal skin and of senile elastosis 

 are indistinguishable; both are quite free of distinctive 

 architecture. Lastly, incubation of small cubes of fresh skin 

 exhibiting senile elastosis with elastase shows typical solubil- 

 ization of the elastic elements therein. The digested areas are 

 negative after Mallory or elastic tissue staining. It would 

 appear that we are dealing with a bizarre type of elastic tissue. 



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DISCUSSION 



McCance: I was fascinated by Dr. Lansing's communication because 

 the possible effect of age on the chemical structure of proteins has 



