Evidence is presented which indicates that certain fluorescent spots observed in raw cotton under ultraviolet light are associated with the prior growth of microorganisms on the fiber. A striking and characteristic type of spot which fluoresces bright greenish- yellow was noted frequently in classers' samples from the 1954 cotton crop grown around Yuma, Arizona, and Brownsville, Texas. It was also, but less frequently, noted in samples from other regions of Texas and occasionally in samples from other states. Spots of this particular type have been shown to be associated with growth on the fiber of the fungus Aspergillus flavus, three principal lines of evidence having been obtained : (1) the very common occurrence of A. flavus in the fluorescent spots; (2) the production of a fluorescence of similar appearance by A. flavus growing on cotton fiber in pure culture; and (3) the similarity of the fluorescent substances from field- and A. flavus -incubated fiber in chromatographic behavior and absorption spectrum. The fluorescent fiber in commercial samples exhibited abnormally high swelling in alkali and decreased strength. A white-fluorescent spot, less striking and less easily recognized than the above, has been found to be associated with certain isolates of the fungus Alternaria sp. Several other common types of microbial growth on cotton prior to harvest were not accom panied by distinct differences in fluorescence as compared with uninfected fiber, indi cating that under the conditions here employed ultraviolet examination is not a general tool capable of detecting all of the types of microbial infection present in commercial cotton.

Tentamos verificar, em algumas séries de experiências a ação oligodinâmica da prata sôbre o vírus da gripe, tipo A, amostra PR8 e tipo A-primo, amostra DL Rio empregando, para tal fim, recipientes, ora recobertos internamente, em delgadíssima camada, pela prata metálica ora contendo-a, sob a forma de pó, de mistura com o próprio material que constitui as paredes do frasco. Neste foi colocado o líquido alantóide contendo vírus verificando-se, de tempos em tempos, o seu poder patogênico para camundongos brancos e a persistência do seu poder hemaglutinante. Pelos resultados acima expostos vê-se que o referido vírus nada sofreu pela ação oligodinâmica da prata, nas condições experimentais descritas ao passo que, concomitantemente a mesma teve efeito ràpidamente mortal para bactérias pertencentes às espécies Micrococcus pyogenes e Escherichia coli. Assim sendo, logo se destaca a importância do fenômeno observado sabendo-se, além do mais, que a ação oligodinâmica, letal ou nociva, se tem verificado sôbre os sêres vivos em geral. Verificamos ainda, no decorrer dessas experiências, que a junção de bactérias não alterou a atividade do vírus quer as mesmas se encontrassem vivas quer mortas. As nossas pesquisas prosseguem com outros vírus, os mais diversos, cumprindo-nos salientar, desde logo, que o processo poderá ser empregado para o isolamento dêsses agentes conforme já o verificamos para o da gripe, em experiência acima descrita. Será uma das decorrências práticas da observação que fizemos, dependendo, as demais, de puro interêsse biológico, de investigações subseqüentes, baseadas na observação inicial que ora apresentamos.<br>In some experiments we tried to verify the silver oligodynamic action upon the influenza vírus, A type, PR8 strain and A-prime, DL Rio strain. In the tests we used clay pitchers covered in the inside parte with a thin layer of silver or with powdered silver mixed into the clay material. The infected allantoic fluid was put into the pitcher and the pathogenic power for mice and the hemagglutination reaction verified at regular intervals. The results expressed in the tables indicated that no alterations were presented by the virus in comparison with the controls. Experiments made with Micrococcus pyogenes and Excherichia coli died in 24 to 48 hours. The reported phenomenon is important because we know that the oligodynamic effect is observed upon microorganisms like bacteria, protozoa and other living beings. The alive or dead bacteria didn't alter the referred properties of the virus. We are stil investigating the phenomenon with other viruses and, now, we emphasize that it can be applied for the isolation of viruses as we verified for the influenza virus. This will be one of their practical applications. We think that many others, from the biologic point of view, may arise based on our first observation here presented.