January 19, 1900.] 



SCIENCE. 



\l\ 



Panlarbea (40) and EhampJwmyia (41), and that 

 the cross-vein marked in — cu in Leptis (Am. 

 Nat., 32; 337, fig. 30) does not exist in the 

 hymenoptera, but is obliterated by the coales- 

 cence of the above-mentioned veins ; M^ is 

 <7«i, and Ou^ is Cuj ; the cross-vein marked 

 m — cu is not homologous with the one so 

 marked in Leptis, but belongs to the arculus ! 

 To account for the vein marked Cu, I should 

 say that it is before the arculus and does not 

 enter in the consideration of the ordinary cases. 

 According to the authors, this vein does not 

 occur in any of the hymenoptera, except Pam- 

 philius. 



If my view is correct, a large part of the 

 peculiarities of the venation of hymenoptera is 

 connected with the great lengthening of the 

 arculus and the shifting of it from the base of 

 the wing. 



The only changes in the designation of the 

 cells which my attempt at elucidation involves 

 are : M, is Cui ; Cu-i is 2nd Cu ; Cu is let Cu ; M 

 is homologous with the cell marked 1st M in 

 Scenopvnus {Am. Nat, 32 ; 339, fig. 36) ; Ji, is 

 the same as the cell marked Snd M in Sceno- 

 ^jnits and the cell marked Min Rhamphomyia 

 (41). 



Charles Robertson. 



NOTES ON INOBQANIC CHEBIISTST. 

 A GOOD illustration of how much material 

 there is in inorganic chemistry which needs 

 reinvestigation, is found in the fact that there 

 has been no general method of forming the sul- 

 fids of the rare earths, nor have any of the sul- 

 flds been obtained in a pure condition, with the 

 possible exception of that of cerium. This gap 

 has now been filled by Muthmann, of Munich, 

 in conjunction with L. Stiitzel. They find that 

 while the oxids are very slowlj' converted into 

 sulfids when heated in a stream of hydrogen 

 sulfid, the anhydrous sulfates are, under the 

 same conditions, very readily converted quanti- 

 tatively into the sulfids. The sulfids of cerium, 

 lanthanum, neodymium andpraseodymium were 

 formed in this way, and their properties, phys- 

 ical and chemical, studied. They are fairly 

 stable in the air at oi-dinary temperature, but 

 are decomposed with evolution of hydrogen sul- 

 fid by warm water or dilute acids. They take 



fire readily on heating in the air, and when 

 finely divided the cerium sulfid often proved 

 pyrophoric. They burn to a mixture of oxid 

 and sulfate. On heating in a current of dry 

 hydrochloric acid, they are readily and quanti- 

 tatively converted into the anhydrous chlorids, 

 and on a small scale this is the best and easiest 

 method of preparation of these chlorids. The 

 study as a whole, which is published in the last 

 Berichte, is a valuable contribution to the chem- 

 istry of the rare earths. 



In a series of experiments by A. Petterson, 

 of Upsala, printed in the Klinische Wochen- 

 schrift (Berlin), the fact is established that in 

 meat and fish preparations, containing 15 fn of 

 salt for the purpose of preservation, a constant 

 and luxuriant growth of microorganisms takes 

 place. From this the conclusion is drawn that 

 the special flavors, odors, consistencies, and 

 colors of salt conserves are chiefly produced by 

 various microorganisms. 



The subject of food preservatives is also dis- 

 cussed from a different standpoint by R. Kayser, 

 of Nuremberg, in the Zeitschrift filr offentliche 

 Chemie. In earlier times, the tendency of vari- 

 ous foods to decomposition was counteracted by 

 drying, smoking, pickling and the like. In 

 some cases special processes were used, as the 

 treating wine with sulfur, beer with hops, etc. 

 At the present day, scientific progress has led 

 to the use of low temperatures, of sterilization, 

 and especially to the use of chemicals. In this 

 last case the demand is made that the preserva- 

 tives used shall not only be harmless in the 

 quantities used, but inert to the human system 

 even in vastly greater quantities than ever used 

 in foods. This demand, it is pointed out, is un- 

 precedented, for it is not complied with under 

 old methods. Common salt, saltpeter and creo- 

 sote are present in these and are not less injurious 

 in quantity than the more recently used boric 

 acid, borax, salicylic acid, benzoic acid, etc. 

 There are no authentic instances on record of 

 injury from the use of any of these in foods, 

 while there are very many instances of injury 

 from foods which, apparently good, were in 

 reality decomposed (presence of ptomains, etc.). 

 The whole subject needs to be treated in a 

 more rational way. 



