1922] Proceedings op Elisiia Mitchell Scientific Society 31 



placed directly upon the target. It is probably the most deadly 

 form of gas attack known. The principal gases used in Livens drums 

 are phosgene and chlorpicrin. 



The 4" Stokes mortar is used for gas, each shell carrying about 

 7 pounds. The rate of fire is very high, 10 rounds per minute being 

 maintained even at night. The range is approximately 1000 yards. 



All of the above weapons are used by gas troops and have the ad- 

 vantage over the Artillery of being able to place very high concen- 

 trations of gas upon the objective. As compared with the Artillery 

 they have a disadvantage as regards the range of the weapon and 

 also as to the accuracy of the weapon. 



The number of gas shell used towards the end of the War was 

 very large, amounting in some cases to 50% and even more of the 

 total shell used. If the entire War is considered probably not much 

 more than 5% of the total shell used were gas shell. Altogether 

 the French filled about seventeen million gas shell. Mustard gas 

 was by far the most effective gas used by the Artillery. 



Methods of gas defense deal with personal protection, such as 

 that afforded by the mask or by protective clothing, and with group 

 protection, such as that afforded by gas alarms and protective dug- 

 outs. Gas protection is also sought by keeping troops fairly well 

 apart or by abandoning gassed areas. 



It is probable that the use of gas combined with aviation will 

 greatly change methods of coast defense and naval offense. 



256th Meeting— March 14, 1922 



H. B. Anderson — Spirocheticidal Action of Arsphenamin (Salvar- 



san, "606"). 



Spirochetes are a class of microscopical organisms which are, al- 

 though placed with the Bacteria, very closely related to the Protozoa. 

 After the discovery of Spirocheta pallida by Schaudinn, who at first 

 classed it with the Protozoa, there were many experiments made to 

 determine the spirocheticidal action of various arsenical compounds 

 such as had been efficient in the treatment of protozoan diseases. 

 Ehrlich discovered a synthetic organic arsenical compound which 

 had very pronounced spirocheticidal action. This he called salvar- 

 san. Soon after this discovery he placed neo-salvarsan on the market 

 too. When the war broke out the allied nations took up the manu- 



