830 SUMMARY OF CURRENT RESEARCHES RELATING TO 



which they excrete for this purpose, and which, like diastase, is soluble 

 in water and precipitated by alkalies. 



5. This ferment acts only diastatically, and does not peptonize ; 

 i. e. it transforms starch into a sugar which reduces copper-oxide. 



6. The ferment itself can act en starch even in the absence of 

 oxygen. 



7. The ferment is excreted by the bacteria even in neutral 

 solutions containing starch ; and under these conditions without 

 action. 



8. The action of the ferment is accelerated in slightly acid solu- 

 tions. 



From these results Wortmann deduces the theory that bacteria 

 produce a ferment which peptonizes albumen, but which has only a 

 diastatic action on starch in the absence of albumen and other sources 

 of carbon. 



Bacteria of Intermittent Fever.* — A. Rozsahegyi confirms the 

 observations of Klebs and Tommasi-Crudeli f with regard to the 

 efficiency of filamentous bacteria in acting as carriers of the contagion 

 of malarial fever. Placing a small quantity of the marshy soil of a 

 malarial district of Hungary in a drop of solution of isinglass, he 

 allowed this to stand in a warm place, when the malarial bacilli 

 shortly made their appearance. When mixed with pure isinglass, the 

 culture invariably succeeded at once ; but if from one of these cultures 

 a drop is taken containing abundance of bacilli and spores, and again 

 placed in pure isinglass, this secondary culture succeeded only in 

 about one-third of the cases. This is attributed by Eozsahegyi 

 to the fact that, in addition to organic matters, the bacillus requires 

 mineral constituents for its nutrition. For the secondary culture, 

 heating to 50°-100° C. reduced the germinating power of the bacillus 

 by about 2 per cent. ; while a temperature between zero and 20 ■ 6° 

 raised it by 50 per cent. Moist heat hence diminishes the germina- 

 ting power, while moist cold increases it. The resting spores were 

 killed only by an exposure for two hours to a temperature of 190°- 

 195°. 



Bacterial Parasite of the Chinch Bug.J — In the course of some 

 experiments upon the chinch bug, S. A. Forbes was annoyed by their 

 rapid disappearance, and, crushing some, examined their fluids under 

 the Microscope. In every case these were found to be swarming with 

 a species of Bacterium not easily distinguishable from B. termo. The 

 observations were many times repeated with every precaution against 

 accidental infection, but with the same results. 



Careful search in the juices of the corn upon which the insects 

 were feeding, failed to discover anything of the kind there, and if a 

 bug were thoroughly washed in a drop of distilled water no bacteria 

 occurred in the water, showing that they were not derived from the 

 surface of the insect. When a number were kept for a week in a 



* Biol. Centralbl., ii. (1882). See Naturforscher, xv. (1882) p. 196. 



t See this Journal, i (1881) p. 287. 



% Amer. Natural., xvi. (1882) pp. 824-5. 



