28 Society for Experimental Biology and Medicine. 



2. Those pupae which become perfect moths are likewise dif- 

 ferent from those which cannot emerge as perfect moths. 



3. The basis for selective elimination is to be sought in corre- 

 lation between the various structures. 



The mating period follows immediately after metamorphosis, 

 when certain individuals with weak mating instinct fail to take part 

 in the production of the next generation, and are thus " sexually 

 eliminated." In order to determine the points mentioned above, 

 pupae of the two species named were isolated as the time for meta- 

 morphosis approached, and upon emergence were given one oppor- 

 tunity to mate. It was therefore possible to compare the pupae 

 of the two classes of mating and non-mating individuals. The 

 results, briefly stated, are : 



1. That even slightly imperfect moths possess very little mating 

 instinct, or in other words, that, with the structural conditions asso- 

 ciated with an imperfect power of emergence, is correlated a low 

 grade of mating ability. 



2. That the mating individuals of the perfect class differ struc- 

 turally to a certain extent from the non-mating ones, but they are 

 very much less variable than the latter class. 



The importance of these results from the standpoint of inher- 

 itance and evolution is sufficiently clear to render extended dis- 

 cussion unnecessary. 



28. " Observations on a serous fluid of unusually high molec- 

 ular concentration : " EDWARD K. DUNHAM. 



The fluid was removed from the pleural cavity of a man suffering 

 from lobar pneumonia. The patient was a scene-shifter in a 

 theater, and had suffered considerable pain in the chest for four 

 months before his admission to the hospital. His occupation re- 

 quired severe labor for brief periods, during which he became 

 much heated, with intervals of leisure and exposure to cold drafts 

 of air. The immediate reasons for his admission were a chill and 

 inability to continue work. There was nothing unusual in the 

 clinical course of the pneumonia or peculiar in his treatment. A 

 few days after he entered the hospital 400 c.c. of a clear serous 

 fluid were aspirated from the affected side of the chest. This fluid 

 was examined on the same day, with the following results : 



