816 



SCIENCE. 



[N. S. Vol. XIV. No. 360. 



nature, the method of investigating them has 

 departed somewhat from the paths usually- 

 followed in determining the composition, ef- 

 fects and r61e, of organic combinations in 

 vegetable and animal organisms. The nature 

 of the enzym is still a matter of much doubt. 

 Of their action we are more sure, and it is 

 along this line that we have become familiar 

 with the nature of some members of this very 

 interesting group of compounds. The r61e of 

 the enzym in the life processes may also in 

 some cases be defined with certitude. 



Beginning with a few, the study of unorgan- 

 ized ferments has brought to light many- 

 others. Out of the growing number some are 

 already put to important uses, -while others bid 

 fair to become of great value to many industries. 

 Dr. Oscar Loew in his studies on tobacco (Rpt. 

 No. 68, Div. of Veg. Phy. and Path. U. S. 

 Dept. of Agr.) goes further in the study of un- 

 organized ferments than ascribing to one a 

 special role and shows the general distribution 

 and seeks a reason for its existence of an 

 enzym, to which he gives the name catalase. 



In the work with this enzym, in which the 

 writer took some part, the most striking char- 

 acteristics were its very general dissemination, 

 its persistence, and its ability to break down 

 hydrogen peroxid. In the examination of a 

 large number of animal and vegetable organs 

 this enzym was found present, in greater or 

 less amount, in every instance. Its diflferen- 

 tiation from other unorganized ferments is es- 

 tablished by a large number o tests with 

 various reagents. Among other characteristics 

 it was found to be more persistent than any 

 other known enzym. This was especially 

 noted in dried vegetable substance as seeds 

 and leaves, being found present in a herbarium 

 specimen of the latter examined after a lapse 

 of over 50 years. 



The ability of catalase to break down hydro- 

 gen peroxid appeared to be its most striking 

 peculiarity, and this led the author to believe 

 that it might perform such a service in the 

 phenomena displayed by living matter. Tests 

 go to show that it belongs to the class of oxi- 

 dizing enzyms and its very general occurrence 

 and uniform actions indicate that it plays some 

 important role in physiological processes. 



From his studies the author gives the follow- 

 ing as the most plausible explanations of the 

 action of catalase in vegetable organism : (1) 

 It destroys instantly the hydrogen peroxid, 

 probably formed in cells during the oxidation 

 caused by the respiration process ; (2) it loosens 

 chemical affinities in certain compounds so that 

 the protoplasm can more easily split or oxidize 

 them. "In other words, catalase might rep- 

 resent 'an aid for fermentative as well as for 

 respirative phenonomena." D. W. May. 



U. S. Department of Agricultuee. 



TOADS KILLED BY SQUASH-BUGS. 



During the past summer the Entomological 

 Department of the New Hampshire College 

 Agricultural Experiment Station carried on in- 

 vestigations on the common squash-bug {Anasa 

 tristis), which has been so abundant in some 

 portions of the State the past season, Mr. 

 Kirkland, in Bulletin 46, Mass. Agr. Exp. Sta., 

 recorded the bug to have been found in the 

 stomach contents of toads ; Mr. Chittenden, in 

 Bulletin 19, 1899 (New Series), U. S. Dept. 

 Agr., states that Dr. Judd likewise found a bug 

 in a toad's stomach. This suggested that the 

 toad is probably an enemy of the squash-bug, 

 and experiments, made to determine this, showed 

 the following interesting results : When a 

 squash-bug nymph o the fifth stage was sud- 

 denly introduced into a half pint, open, wide- 

 mouthed specimen jar containing a half grown 

 live toad, so that the Batrachian would get the 

 full effects of the pungent fumes given oflf by 

 the bug, the toad was thrown into a temporary 

 stupor, the efi^ect being similar to that of chloro- 

 form. As the number of bugs was increased 

 the effect on the toad was increased. When as 

 many as seven bugs were introduced the toad 

 fell into a profound stupor and died in the 

 course of twenty-four hours. 



On September 8, an adult, that had been kept 

 in the laboratory vivarium with a scant food 

 supply for several days, was placed in a quart 

 jar of the same construction as the one men- 

 tioned above, and eight bugs were introduced.; 

 these bugs, however, had been so much dis- 

 turbed previously that the source of the pun- 

 gent secretion had been temporarily exhausted. 

 The toad hesitatingly devoured three, after 



