STUDIES ON THE PANCREAS OF THE GUINEA PIG 335 



Meantime the same statements have been advanced by Vincent 

 and Thompson ('07) and by Laguesse ('10). Vincent and Thomp- 

 son made the effect of inanition the subject of experiment in 

 dogs, cats, pigeons and frogs. Of the result of these experiments 

 it is impossible to judge, for the authors content themselves with 

 general statements, and give no indication of the number of experi- 

 ments made in each case, nor of the character of the numerical 

 comparisons, except the statements that in the cases of two dogs 

 the ratio of islets in a field of the resting pancreas to those in a 

 field of the inanition pancreas is 3 to 16, and that in the pigeon by 

 cutting out and weighing the pieces of paper in drawings of ten 

 successive sections they found the ratio of islets in the inanition 

 pancreas to that of the resting pancreas as 4.22-0.93. One can- 

 not avoid, under these circumstances, asking how many normal 

 resting pancreases were actually counted in each species in order 

 to establish the normal range of variation and what were the max- 

 imum and minimum counts. 



Laguesse ('10) on the other hand, has proceeded with his usual 

 caution in similar experiments on pigeons giving the records in 

 full of the counts made in single fields of the microscope of two 

 series of pigeons which he had previously acclimated to the labo- 

 ratory. Each series shows in sections taken at random from cor- 

 responding portions of the pancreas a higher average number in 

 the inanition pancreases. It is noteworthy, however, that the 

 controls of one series are as high in islet content as the inanition 

 pancreases of the other series. Laguesse's results, while en- 

 titled to the highest consideration by reason of the care with which 

 they were carried out, are still subject to the objections raised 

 against the method of estimation of islet content by the exami- 

 nation of isolated sections, namely, that this method involves 

 primary assumptions as to the equality of distribution of the 

 islets in a given portion of the pancreas, which, in the guinea pig, 

 I have proven by actual counts and weighings not to be well 

 founded. Furthermore, there is always in this method the sub- 

 jective element of unconscious selection, however scrupulous one 

 may be in the selection at random of the sections to be counted. 



