September 2S, 1S83.] 



SCIENCE. 



433 



details of the differentiation of the lame are care- 

 fully described. 



I cannot conclude this notice without referring to 

 the admirable manner in which this valuable memoir 

 is written, and the great clearness with which the 

 facts and conclusions are presented. 



Charles S. Minot. 



EXPERIMENTS TO DETERMINE THE 

 GERMICIDE VALUE OF CERTAIN 

 THERAPEUTIC AGENTS. 



In the American journal of medical sciences for 

 April. Dr. Sternberg gives an account of his study of 

 this important question. The objects of the author 

 were. — 



To ascertain the exact value, as germicides, of some 

 of the agents most frequently employed in medical 

 and surgical practice, with a view to the destruction 

 of pathogenic micro-organisms, liypothetlcal or de- 

 monstrated. 



To compare this value, established by laboratory 

 experiments, with the rcsuUs of clinical experience, 

 for the purpose of ascertaining what support, if any, 

 the germ-theory of disease receives from modern 

 therapeutics. 



Assuming that the active agent in infective mate- 

 rial is a living micro-organism, or 'germ,' disinfec- 

 tion will be accomplished by those chemical agents 

 only, which have the power of destroying the vitality 

 of this organism. We reijuire to know: — 



a. What is the absolute germicide power of various 

 disinfecting agents, in order to select the best with a 

 view to economy and efficiency; 



b. Are all disease-germs destroyed by these agents 

 in the same proportion? and, if not, 



c. What agents are the most available for special 

 kinils of infective material? 



In therapeutics we should know, in addition to 

 this : — 



d. What is the minimum quantity of each of these 

 agents which will restrict the multiplication of each 

 specific disease-germ in a suitable culture-medium ? — 

 this with reference to medication, with a view to ac- 

 complishing a like result within the body of an in- 

 fected inilividual. 



Evidently, any thing like a complete answer to these 

 •questions is quite impossible in the present state of 

 knowledge, and we must content ourselves with such 

 partial or approximate answers as can be obtained by 

 laboratory experiments upon the comparatively small 

 number of pathogenic organisms which abound in 

 organic liquids undergoing putrefaction. 



The experiments were conducted by using small 

 sealed flasks containing bouillon free from micro- 

 organisms. The smallest quantity of a fluid contain- 

 ing such organisms introduced into one of the flasks 

 would cause it to ' break down ' within twenty-four 

 hours, it being exposed during this time to a temper- 

 ature of 100° F. 



To test the germicide power of a chemical reagent, 

 living bacteria are subjected to its action in a known 

 proportion for a given time, and are subsequently used 



to Inoculate sterilized bouillon in one of the flasks. 

 Failure to multiply in this fluid, when exposed for 

 twenty-four hours or more to a temperature of 100° 

 F., is evidence that reproductive power — vitality 

 — has been destroyed by the reagent used. On the 

 other hand, failure to disinfect, i.e., to destroy the 

 vitality of the bacterial organisms used as a test, is 

 shown by the 'breaking-down' of the culture-fluid. 



Standard solutions of the reagents to be tested are 

 prepared with distillled water. The germs are ex- 

 posed, in small glass tubes, to the action of these 

 agents for two hours. The tubes are sterilized in the 

 flame of an alcohol-lamp immediately before each ex- 

 periment; they are open, and covered by a bell-glass 

 during the time of exposure. 



At the end of the time of exposure, a small quan- 

 tity of the fluid from one of the tubes is introduced 

 into a flask containing sterilized bouillon, and this is 

 exposed to a temperature of 100° F. for twenty-four 

 hours. 



The micro-orfianisms ii^hich hare been vsed in the ex- 

 perinientsherein reporteil, to test the germicide power 

 of the reagents named, were obtained from the fol- 

 lowing sources: — 



a. A micrococcus from gonorrhoea! pus. 



b. A micrococcus from pus obtained from an acute 

 abscess (whitlow) at the moment that it was opened 

 by a deep incision. This micrococcus is morphologi- 

 cally identical with the preceding. 



c. A pathogenic micrococcus, having distinct mor- 

 phological characters obtained from the blood of a 

 septicaemic rabbit. 



d. Bacterium termo. and other bacterial organisms 

 (micrococci and bacilli) from ' broken-down ' beef-tea 

 which had been freely exposed to the air. 



In the following t.able, which is arranged according 

 to the germicide value of the agents named, all ex- 

 periments are given in which the micrococcus from 

 l)us was used as a test. 



Mercuric bicliloride (0.005 per cent;, efficient in the pro- 

 portion of one part in 20,000 



Potaftsium permanerftnnle (0.12 per cent), eflicient in the 



proporlion of one part in 833 



Iodine (0.2 per cent), eflicient in the proportion of one 



part in 600 



Creosote (0.5 per cent), efficient in the proportion of one 



pari in 200 



Sulphuric acid (0.5 per cent), efficient In the proportion of 



one part in 200 



Carbolie-aciU (1 per cent), ellicient in tlie proportion of 



one part in 1**0 



Hydrochloric acid (1 per cent), efficient in the proportion 



of one part in tW* 



Zinc chloride (4 per cent), efficient In the proportion of one 



part in *" 



'I'inc. fcrrl cliloridi (4 per cent), efficient In the proportion 



of one pan In 25 



Salicylic odd diasolvcd by Bodium borate (•» per cent), 



efficient in the proportion of one part in .... 26 

 Caustic poiaah (10 per cent), efficient in the proportion of 



one part in 10 



Citric acid (12 per cent), efficient in the proportion of one 



part in 8 



Chloral hydrate (20 per cent), efficient In the proportion of 



one part In 6 



The following-named reagents, as far as the experi- 



