102 Discussion 



have doubts. Finally I discovered that this was spirocercosis of the dog, 

 which is a very common disease in our country. In many cases, I found 

 these parasites which produce many interesting changes, especially in 

 the aorta and large arteries of the dog. I have since proved that in 

 spirocercosis the parasite itself produces elastolytic enzyme, and it is 

 interesting to note that whenever the parasite is found in the wall of 

 the aorta the elastic fibres are all dissolved and some of the dogs die from 

 rupture of the aorta. 



The next step was to try to find out what the importance of this finding 

 is in the human being. I wanted to know whether elastase is present in 

 the pancreas of healthy individuals, and in what quantities. I have had 

 the opportunity to investigate the pancreas from people who died as a 

 result of an accident, and using fresh material received from the Medico- 

 Legal Institute, I proved that if healthy individuals died as a result of 

 an accident, great quantities of elastase were present in their pancreas. 

 I compared this finding with the findings in diseased individuals, 

 especially the findings in adults, and found that the quantity of elastase 

 decreases with age, so that in old age — especially at the age of about 60 

 — scarcely any elastase is seen in the pancreas. 



Arteriosclerosis may be correlated with the disappearance of elastase 

 from the pancreas. Elastase is of decisive significance not only in the 

 decomposition of elastic fibres but also in their synthesis, and is essential 

 to the maintenance of intact elastic fibres. Lack of elastase leads to the 

 degeneration and disappearance of the elastic fibres. 



At first we found that the elastic fibres of young and old individuals 

 are dissolved in a different manner, whereas those in the arteries of new- 

 born children are not dissolved, even after three days ; so if we take 

 histological sections from the aorta of the newborn or very young child, 

 and put them in elastase solution, the elastic fibres are not dissolved and 

 after three days only slight solution can be observed. On the contrary, 

 if we take sections of the aorta or elastic arteries of an old individual, 

 then the elastic fibres are readily dissolved. I have found that in 

 individuals aged over 60 years the elastic fibres are dissolved in twenty 

 minutes, and this proves that there are differences in the structure of the 

 elastic fibres in young and in old individuals. 



Although we continued to work along these lines, no one in our circle 

 of research believed this finding and, therefore, it was of great help to us 

 when Prof. Tunbridge's school in Leeds took up the problem and it was 

 a great pleasure for us when Prof. Tunbridge and his collaborators, 

 especially Hall and Reed, were able to prove that elastase works in this 

 way. Since then, Prof. Tunbridge and his school have carried out 

 important investigations along this line in that they have combined this 

 line of research with electron microscopic investigation of dissolved elastic 

 fibres, and they have made very important contributions to the data on 

 structure of elastic fibres. 



In the United States, Lansing and co-workers have taken up this 

 study of the structure of elastic fibres, and a similar study was begun by 

 Schwarz and Dettmer in Berlin and by Findlay, Pepler and Brandt in 

 South Africa. During these studies, the question was asked "Are the 



