89 



of whom found the relative proportion of islands greater in the splenic 

 end than in the head, while in the body the number approached that 

 of the head. As has been indicated above, these observers have noted 

 several cases in which the proportion of islands in the head, tail and 

 body w^as the reverse of the usual condition, being greatest in the head. 

 Instances were also recorded in which the proportion for the three 

 parts was about the same or varied but little. Of the 65 pancreases 

 examined by Heiberg {1906 and 1910) the single area showing the 

 greatest number and proportion of islands was found in the head. 

 In subject 7, in which the proportion of islands decreases from 

 head to tail, an explanation might be sought in a possible error in 

 enumeration. Since only a relatively small proportion of the human 

 pancreas when stained by this method can be counted by one indi- 

 vidual, before fading occurs, it might be that the few^ pieces taken 

 for counting happened to be from those areas of the head in which 

 the islands are most numerous, and hkewise many of those from the 

 areas in the splenic end in which the islands were least numerous. 

 On the other hand the discrepancy in this case may be accounted for 

 by the relatively greater size of the individual island in the splenic 

 end and in the body than in the head, of such greater size in fact that 

 the relative volume of islet tissue was greatest in the splenic end. 

 Indeed the great number of large and extremely large islands, 

 especially in the splenic end, was one of the characteristice of this pan- 

 creas. These were large, round or oval bodies, well circumscribed 

 and solid. They took on a very deep bluish green stain. Time did 

 not admit of measuring the diameter of these larger islands. The 

 number of very small islands was not great and a hasty search with 

 the higher power of the microscope indicates that the very small 

 islands, 1 to 6 cells, as found in the pancreas of the younger guinea 

 pigs, were wanting, or, at most, were extremely scarce in this pancreas. 

 In this connection it was also noted that islands of a racemose or 

 fusiform shape, found both by Bensley and Laguesse in younger 

 animals and observed by myself in rabbits and guinea pigs in which 

 the pancreatic duct had been ligated several months previously, were 

 extremely rare or lacking entirely. Only one island of a fusiform 

 shape was noted. This islet was irregularly oblong and possessed 

 two knob-like branches. It was a solid mass of island tissue and did 

 not have the more or less numerous racemose appendages which are 

 found in the islands of the experimental animals. 



