GERMICIDES. 193 



extent sufficient to exclude rapid-growing surface organisms from participation in the 

 subsequent poured-plate cultures, so that pure growths can be obtained without difficulty 

 from deeper portions of the plants. 



So far as known to the writer no serious attempts have been made to try the newer 

 germicides on plant parasites. A very few of these may be mentioned. Atoxyl, known 

 chemically as arsenic-acid anilide, or arsanilic acid, has been used during the last few years 

 for injection into the spinal cord in cases of sleeping sickness with a view to destroying the 

 trypanosomes. Statements respecting its value are conflicting with the preponderence of 

 the evidence in favor of the use of the germicide. It is undoubtedly only a makeshift till 

 something better is found. Atoxyl is much less poisonous to the higher animals than white 

 arsenic, but very deadly to some of the lower forms. Some of the more recently introduced 

 related substances such as atoxyl acetyl or arsacetine, and especially arsenophenylglycin, 

 or arsenophenylglycollate of sodium, are still more efficient against trypanosomes and at 

 the same time less poisonous to the higher animals (mice, rats, guinea pigs, rabbits, dogs, 

 horses). This latter salt, which, according to Ehrlich, is a little less toxic than atoxyl (but 

 two to four times less toxic according to Roehl) is said to have a very high therapeutic 

 value. A single dose is said to have cured an animal suffering from an experimental 

 tripanasomiasis . 



The most-talked-about substance at present is the dioxydiamidoarsenobenzol from 

 Ehrlich's laboratory, commonly called No. 606 and also salvarsan. A single dose of this 

 substance if properly administered is said to be sufficient to destroy every vestige of Tre- 

 ponema pallida in the body of a man. But here again conflicting statements are rife (191 1). 



Argyrol is an organic silver salt now much used by oculists and others. There are 

 various other similar silver compounds possessing some of the germicidal properties of 

 nitrate of silver without its caustic properties, e. g., protargol, argonin, albargin, largin, 

 saphol (formaldehyd, nucleinic acid and silver). Some of these organic silver compounds 

 are strongly germicidal without being very injurious to the animal body, e. g., argonin, 

 argyrol, albargin. 



Persistent claims have been made by the manufacturers for the high disinfectant power 

 of cyllin, and some of these claims appear to be borne out by scientific tests. Cyllin appears 

 to be some sort of a phenol or mixture of phenols. It is said to be much less poisonous than 

 carbolic acid, and twenty times as efficient, i.e., nearly or quite as germicidal as mercuric 

 chloride. It is advertised in reputable journals as "non-toxic. " 



Aniodol, a French disinfectant, has been recommended recently as a substitute for 

 iodoform. It is said to be highly germicidal and may be used as a powder or as a soap. It 

 contains neither mercury nor copper. 



Cook's asepso soap has been recommended by the Journal of Tropical Medicine. This 

 contains 3 per cent biniodide of mercury. One gram of the soap in 60 cc. of water is said 

 to be equivalent to i : 2000 of the biniodide of mercury, and the lather of the soap is supposed 

 to be still more effective. It is said to be a remedy for Favus. 



For notes on the newer germicides see back volumes of the Journal of Tropical Medicine 

 and Hygiene, Bulletin de 1'Institute Pasteur, and New and Non Official Remedies, 1911, 

 Press Am. Med. Asso., Chicago. 



The writer made several tests of the St. Laceleau soap (see Vol. I, p. 253) using spores 

 of Bacillus subtilis. It appeared to be without sensible restraining effect on this organism, 

 i.e., B. subtilis grew readily in bouillon after exposure to 10 per cent solutions for 30 minutes, 

 and that, too, without a preliminary washing of the spores. Even when the soap was added 

 to agar in the proportions recommended by Konradi it did not prevent the growth of 

 bacteria. The particular cake tested had been out of the factory three years, but had been 

 recently removed from the box and original tinfoil wrappings and was unchanged in appear- 

 ance. 



