1908 Journal of Applied Microscopy 



CURRENT BACTERIOLOGICAL LITERATURE. 



H. W. CONN, Wesleyan University. 



Separates of Papers and Books on Bacteriology should be Sent for Review to H. W. Conn, 

 Wesleyan University, Middletown, Conn. 



Reed, Walter, and Carroll. James, of the U. S. These investigators have already ac- 

 Army. The Etiology of Yellow Fever. q^jj-gj ^^ international reputation by 



the discovery that the mosquito is the means of distributing yellow fever. More 

 recently, they have conducted investigations for the purpose of determining, if 

 possible, the cause of this disease, and they presented at the last meeting of the 

 American Bacteriologists an abstract of their results as follows : 



They have ascertained that, in yellow fever, the blood serum of a patient, 

 which has been filtered through a Berkefeld laboratory filter, is still capable of 

 producing this disease when subcutaneously injected in small quantity (1 c. c.) 

 into non-immune beings. They are able to report an attack of yellow fever after 

 the usual period of incubation, in two out of three individuals thus treated, 

 and to state further that the blood drawn from one of the cases produced by the 

 injection of the filtered serum was capable of producing an attack in a third in- 

 dividual, when injected in small quantity ; thus proving, as they believe, that the 

 specific agent had really passed through the filter. They were also able to show 

 that the blood in yellow fever, when heated to a temperature of 55° C for ten 

 minutes, is quite innocuous if injected into susceptible individuals. The specific 

 agent of yellow fever, therefore, is destroyed or markedly attenuated by this de- 

 gree of heat. H. w. c. 



Saul. Bertrage zur Morphologie des Typhus The author has contributed a new 

 Bacillus und des Bacterium coli commune. method of the study of bacteria which 

 oc . p. 44, 190 . j^^ thinks likely to give additional data 



for a proper differentiation of species. The method is based upon the well 

 known fact that each species of bacterium produces a type of colony which is 

 characteristic, but Saul insists that the characteristics are properly developed only 

 after the colony has had a long time to grow. The new method devised consists 

 of sowing the species in question in rather deep layers of agar and such a small 

 number upon each plate that the colonies are widely separated from each other. 

 The colonies are then allowed to develop for several months. After such long 

 growth the agar is hardened by the use of formaldehyde, and sections made for 

 study with the microscope. The author finds that closely allied species may pro- 

 duce colonies which are quite similar to each other when young, but after long 

 culture of this sort develop distinctively characteristic colonies which are easily 

 differentiated by the microscopical study of colony sections. In the present paper 

 he describes and figures colonies of the typhoid bacillus and the colon bacillus, as 

 well as of a Staphlococcus. The colonies appear quite identical in early stages, 

 but when allowed to develop for several weeks and then studied by sections, they 

 prove to be totally unlike each other and each characteristic of its own species. 

 The author believes that this method of study will give a new method of differ- 

 entiating closely allied bacteria. Certainly the figures given, which are taken 

 from photographs, show these organisms whose colonies so much resemble each 

 other as ordinarily studied, produce at the end of their growth quite different 

 appearances. To what extent the method of study may be practical is a little 

 doubtful, inasmuch as, at best, it requires many weeks before the differential 

 characteristics of the colony are sufficiently developed to be studied. 



H. w. c. 



