xcii GENERAL SUMMARY OF SCIENTIFIC AND 



acid of Jamieson; the other a new body, which he calls thi- 

 ammelin. 



Hesse has given some simple methods of testing the cin- 

 chona alkaloids. He distinguishes quinidine from quinine, 

 cinchonine, and cinchonidine by means of the behavior of 

 water and ammonia with their iodhydrates. If to half a 

 gramme of salt to be tested ten cubic centimeters of water 

 be added, the whole warmed to 60 C, and half a gramme 

 of potassium iodide be added, allowed to cool, and after the 

 lapse of an hour filtered ; then, if the quinidine be pure, no 

 turbidity results on adding a drop of ammonia. A precip- 

 itate under these circumstances proves the presence of one 

 of the other three alkaloids. 



Howard has made an examination of the bark known as 

 Cinchona pelleter ana, in order to prove finally the existence 

 or non-existence of the alkaloid aricine. His results confirm 

 those of other observers, and point strongly to the existence 

 of aricine as a distinct alkaloid. 



Gorup Besanez notices the introduction into commerce 

 from Manilla of a brown extract from Echitas scolaris, a tree 

 belonging to the Apocynacea3, as a febrifuge, under the name 

 Ditain. He succeeded in extracting from it a crystallized 

 non-volatile alkaloid. It is offered as a substitute for qui- 

 nine. 



Jobst and Hesse subsequently made an exhaustive investi- 

 gation of dita bark, which came from the Philippine Islands. 

 From it had been obtained by Gruppe the substance called 

 ditain, which the authors believe to be of uncertain composi- 

 tion. They confined their examination to the bark itself, 

 and obtained from it several bodies, to which they give the 

 names ditamin, echikautschin, echicerin, echitin, echitein, and 



echiretin. 



PHYSIOLOGICAL CHEMISTRY. 



In Physiological Chemistry, Boehm lias continued his ex- 

 periments on the respiration of water plants. He finds that 

 much less oxygen is consumed by them than by land plants, 

 and correspondingly much less carbonic acid is evolved. In- 

 deed, he thinks the relation between the two much the same 

 as between ^ill-breathing and warm-blooded animals. When 

 dead, these water plants undergo a fermentation, attended 

 with the absorption of hydrogen. He has more recently 



