ENTOMOLOGY

CHAPTER XXVIIDiseases Transmitted by the CockroachW. Dwight PierceAs cockroaches are so often found in houses and especially apt tofrequent garbage al).d waste about a house, and frequent the food in thekitchen and on the table, it can readily be seen how easily they mighttransmit disease in case they are capable of carrying the organisms ontheir body or of retaining them in their systems. The cockroach feedson filth of many kinds and goes straight from this filth to food. As itfeeds on the food it contaminates the same with its feces causing noxiousodors which often ruin the food. We owe to Cao, the Italian investigator,our principal knowledge of the manner in which the cockroach can transmitdisease organisms. Cao worked with the bacteria which might befound in food and in carcasses and he may be said to have covered thegreater part of the bacterial organisms which the cockroach is mostlikely to be able to transmit. There can be no question of the desirabilityof controlling roaches in houses, hotels, and eating places. The necessityof this is the greatest in public eating houses where the roaches can feedon sputum and debris left by customers or by employees. A filthy employeeand a cockroach-infested restaurant make a combination to befeared.In the following pages will be found a summary of the records whichhave been made of the role of cockroaches in the transmission of organisms,es'p~cially disease organisms.PLANT ORGANISMSTkallophytq,: Fwngi: CoccaceaeMicrococc~ nig;ofa8ciem Northrup, cause of an insect bacteriasis,has been experimentally transmitted to Periplaneta americana by No!thrup.Sarcina alba Eisenberg has been isolated from the feces of Blattaorientalia by Cao in several series of experiments, but in no case was itfound to be pathogenic after passage through the cockroach, even whenfed in pure culture, or with other foods. In experiments with other383