The macroscopic slide agglutination method has been more or less generally known for years. The value of the method, however, has not been generally appreciated, probably due to the fact that most of the serums employed for identification purposes have not been sufficiently active to give an immediate or prompt agglutination even in low dilutions. Coca (1) utilized the method in cholera examinations and, to our knowledge, he was the first to publish a description of the method. We have utilized it for some years as a routine in examinations of feces for members of the typhoid-paratyphoid dysentery types (2) and also as an aid in the search for meningococcus carriers (3). As very potent sera become more generally available its use will undoubtedly spread to most laboratories.
There is one inconvenient feature in the method which we believe to have overcome by the device here reported.