234 



Scientific Proceedings (121). 



It is not definitely established whether it is a test for anti- 

 toxin ; it is possible that the phenomenon may be due to agglutin- 

 oids, or to a diphtheria antibody not noted heretofore. 



Nicolle, Debains and Cesari 4 have described a qualitative test 

 for toxin and antitoxin which is based on a precipitin reaction- 

 It is evident from the results above that while the test may be 

 specific for the diphtheria bacillus and for the other organisms 

 used by them, it should be subjected to further investigation 

 before it can be accepted as specific for toxin and antitoxin as 

 defined by Ehrlich's guinea-pig test. 



101 (1848) 



Action of some purin derivatives on the isolated bronchus. 



By DAVID L MACHT and GUI CHING TING. 



[From the Pharmacological Laboratory, Johns Hopkins University, 



Baltimore, Ma 1 .} 



In connection with a study of the effects of various drugs on 

 the isolated bronchi of pigs the authors studied a number of purin 

 derivatives. The effects of caffein or trimethyl xanthin in doses 

 of 1-20 mgm. in 25 c.c. of Locke's solution gave the following 

 results; small doses produced no effect on bronchial muscle or 

 occasionally a very slight constriction. After large doses of caffein 

 a little relaxation of the normal bronchial preparations was noted. 

 When, however, such bronchial preparations were first brought 

 into a state of high tonus or contraction, as for instance on treat- 

 ment with muscarin, the relaxing effect of a subsequent dose of 

 caffein was much more marked. On the whole, however, the 

 results obtained indicated that caffein has a very weak dilator 

 effect on the bronchus. 



Following experiments with caffein, observations were made on 

 the effects of theobromin or 1-3 dimethyl-xanthin and theocin or 

 3-7 dimethyl-xanthin. ' It was found that both dimethyl-xanthins 

 produced much greater broncho-dilatation than trimethyl-xanthin 

 or caffein. The authors were unable to obtain a mono-methyl 

 xanthin but they did study the effects of xanthin itself. Although 



1 Nicolle, Debains and Cesari, Cotnp. rend., 1919, clxix, 1433- 



