NOYEMBEB 8, 1907] 



SCIENCE 



631 



portant lipoids of the cell, perhaps with the leci- 

 thin, and in so doing changes their normal rela- 

 tionship to the other cell constituents, through 

 which an inhibition of the entire cell chemism 

 results. It also becomes evident that the narcosis 

 immediately disappears as soon as the loose, re- 

 versible combination, which is dependent on the 

 solution of the tension, breaks up. It follows 

 further that substances chemically absolutely in- 

 different, as the volatile saturated hydrocarbons, 

 can act as narcotics. 



In the second lecture. Professor von Noor- 

 den states " the modern problems of met- 

 abolism " in his usually interesting style. 

 Some of the statements' in this lecture might 

 be criticized, but the reviewer has no desire 

 to be captious, and when he notices that nearly 

 two years have passed since the lecture was 

 given and probably all of that since it was 

 prepared he is ready to admit that it is only 

 just not to be too critical. The confusion 

 of erepsin with the cellular proteolytic fer- 

 ments would not be made now, and the fact 

 that the circulating proteins are strictly spe- 

 cific for every species of animal seems to be 

 abundantly demonstrated by biologic tests, 

 which are much more delicate than chemical 

 analyses in distinguishing between proteins. 

 Professor von Noorden points out clearly that 

 the greatest interest and importance are now 

 attached to the study of the intermediary 

 products of metabolism. If the protein mole- 

 cule is wholly disrupted into amino-groups in 

 the alimentary canal, are these all or in great 

 part synthesized into body proteins or are 

 they treated as waste, converted into urea and 

 thrown into the sewer? Is the man who 

 follows Voit's average and eats 118 grams of 

 protein a day simply wasting his energy in 

 the manufacture of amino-aeids which serve 

 neither bone, muscle nor brain, but only tax 

 the liver and fatigue the kidney? These are 

 some of the questions that are now puzzling 

 the physiological chemist, but he is a lusty 

 young fellow and will solve the riddle by and 



by- 



Professor Novy speaks interestingly and 

 somewhat at length " on trypanosomes." 

 Probably no other branch of microbiology has 

 been developed so rapidly as that of proto- 



zoology and no other promises more benefit to 

 mankind. While the bacterial diseases pre- 

 dominate in temperate regions, the question 

 of the development and the civilization of the 

 tropics depends largely upon man's ability to 

 destroy the protozoal parasites and the scien- 

 tist must be the pioneer in this work. Novy's 

 discovery of the methods of growing the try- 

 panosomes in artificial cultures is a long step 

 in the right direction. In 1841 Valentin re- 

 ported the first of this large class of parasites 

 in the blood of the salmon and a year later 

 Gruby found a first cousin in the frog and pro- 

 posed the generic name, Trypanosoma. 

 During the sixth decade of the last century 

 similar parasites were found in moles, rata 

 and mice, but these findings were practically 

 ignored until Lewis in 18Y7 made his classical 

 contribution to the subject. Three years later 

 Evans found a trypanosome in the blood of 

 animals suffering from a disease ajSlicting 

 horses and camels in India and known as 

 surra. In 1894 Bruce began his studies of 

 the tsetse-fly disease known in Zululand as 

 nagana and demonstrated that it was due to 

 a trypanosome which is transmitted from in- 

 fected to healthy animals by the fly. This 

 disease was observed by Livingstone and is 

 widely distributed over middle and southern 

 Africa, extending up the west coast to Sene- 

 gambia and on the east to the Eed Sea. It 

 affects the horse, mule, donkey, dog, ox, cat 

 and many wild animals. Indeed, the chief oc- 

 cupation of the tsetse-fly seems to be to trans- 

 mit the trypanosome from wild to domesticated 

 animals and in the horse, donkey and dog the 

 disease is said to be invariably fatal. More- 

 over, the tsetse-fly seems to have a monopoly 

 in this business, since it has been shown that 

 infected animals may be kept in the midst 

 of uninfected ones in regions where this fly 

 does not exist. Two Togo ponies were found 

 in the Berlin zoological gardens to be infected 

 and notwithstanding the presence of other 

 biting insects the disease was not transmitted 

 to other animals in the gardens. In the wild 

 animals of Africa this parasite is either 

 wholly harmless or kills so slowly that the 

 supply does not run out. Since the rinder- 



