24 PROFESSOR D. J. CUNNINGHAM 



specimens, I was soon convinced that here we had a real hypertrophy, and that even 

 an excessive or spasmodic contraction of the muscle-fibres could not give rise to the 

 enormous thickening of the musculature seen in these cases. 



It is evident that Ibrahim (26) appreciates the force of Thomson's argument, that 

 to obtain a muscle-hypertrophy it is necessary to assume an antecedent muscle-activity, 

 because he puts forward a morphological suggestion to account for the hypertrophy in 

 the stenosed pyloric canal being the antecedent and primary condition. 



From an examination of three children which had been born prematurely in the 

 seventh or eighth month, and which had lived several weeks, Ibrahim has gained the 

 impression that the pylorus presents at this period a relatively greater size, and 

 possesses a relatively greater amount of muscular tissue, than at later stages of 

 development. He consequently suggests that the stomach passes through a develop- 

 mental phase similar to the condition present in the infantile uterus, in which the 

 fundus is small, and the cervix of inordinate size. Having reached this conclusion, 

 the step which leads to the hypothesis which he puts forward is comparatively simple. 

 He considers that the stenosed pylorus of the infant is to be regarded merely as the 

 retention of a transitory developmental condition present in the stomach from the 

 seventh to the eighth month of intra-uterine life. 



Unfortunately, the force of this somewhat far-fetched argument is weakened by 

 the fact that it rests upon an altogether fallacious basis. There is absolutely no ground 

 for the statement that the musculature of the pyloric canal in the foetus at this stage in 

 its development is relatively more strongly developed than in the later stages. So 

 far from this being the case, it is evident from sections in my possession that at 

 this period of development it is more weakly expressed than in the full-time foetus. 



None of the views on the many complex questions involved in pyloric stenosis 

 in the infant can be considered as being altogether satisfactory ; but it appears to me 

 that Thomson's hypothesis, in the present state of our knowledge, best meets the circum- 

 stances of the case. It is true that Ibrahim puts forward several more or less cogent 

 arguments against it, and he points to Finkelstein's case, in which there was excessive 

 development of the longitudinal muscle-fibres of the pyloric canal, as being unfavourable 

 to this view.* So far from this being the case, the hypertrophy of this layer, which 

 was present in a marked degree in all the specimens I have had the opportunity of 

 examining, may be looked upon as the natural accompaniment of a prolonged spasm 

 of the sphincteric cylinder and ring. As we have noted, there is good reason to believe 

 that these longitudinal fibres have an important part to play in dilating the pyloric 

 opening. Spasmodic contraction of the sphincteric apparatus would necessarily lead 

 to excessive exertion on the part of the antagonistic longitudinal fibres, and thereby 

 lead to an increased development of this layer. The fusiform shape which the pyloric 



* It may be as well to say that Finkelstein's (13) statement on this matter and the diagram which he gives are 

 not satisfactory, and raise doubts as to whether he has correctly differentiated between the two muscle-layers in the 

 wall of the pyloric canal. 



