March 7, 1902. J 



- SCIENCE. 



369 



The conclusion from these facts is that 

 such encapsulated organisms should with 

 hesitation be separated from Streptococcus 

 pyogenes, unless well-marked cultural dif- 

 ferences can be shown to exist. 



Branching in Bacteria, ivith Special Refer- 

 ence to B. diphtheria: Hibbert W. 

 Hill, M.D., Boston Board of Health 

 Bacteriological Laboratory. 

 The chief problems considered divide 

 themselves into morphological and physio- 

 logical or developmental problems. The 

 general subject is one of fundamental im- 

 portance, theoretical and, in its relation to 

 diagnostic work, practical. 



The principal hypotheses to be consid- 

 ered as offered to explain branching may 

 be briefly stated: (1) Accidental oppo- 

 sition. (2) Budding from single-celled 

 rods. (3) The turning aside of a medial 

 cell in a chain of closely connected cells, 

 supposed to compose the larger bacterial 

 rods, and the subsequent ' chaining out ' of 

 such a cell (Nakanischi's view). (4) The 

 development of a medial melochromatic 

 granule of a new rod. (5) Involuntary 

 changes. 



The writer describes the results of the 

 examination of individual bacilli develop- 

 ing in a moist warm chamber under the 

 microscope and concludes: (1) That de- 

 generative (involutionary) changes do at 

 times give rise to distortions distantly sim- 

 ulating branches. (2 and 3) That active 

 branching, by apparent budding resulting 

 in multiplication, does occur in young 

 (five to ten hours old) cultures on agar. 

 (4) That various modifications of the pro- 

 cess exist. (5) That such branching may 

 be reversionary or evolutionary in charac- 

 ter, but involutionary only in the case 

 noted above (1). 



A review of the literature and considera- 

 tion of nomenclature follow, and a number 

 of drawings are given in the full article. 



' Hanging Block ' Preparation for Micro- 

 scopic Observation of Developing Bac- 

 teria: Hibbert W. Hill, M.D., Boston 

 Board of Health Bacteriological Labora- 

 tory. 



The writer cuts a cube of nutrient agar 

 from a Petri dish full of solidified jelly. 

 The organism to be examined, as an emul- 

 sion in water from a solid culture, or as a 

 drop of broth from a liquid culture, is 

 spread upon the upper surface of the 

 agar, as in making an ordinary smear prep- 

 aration on glass. After drying the cube at 

 37°C. for ten minutes, a clean cover-slip is 

 applied to the inoculated surface and sealed 

 in place by running a little melted agar 

 round the edges of this surface. The cov- 

 er-slip is then placed over the opening in 

 the moist chamber, the agar block lower- 

 most, and the microscope focused upon the 

 bacteria. For organisms growing best at 

 37° C. some form of warm chamber is nec- 

 essary. The writer describes two such 

 warm stages, devised by himself, and a 

 very simple method of securing a circula- 

 tion of warm water through them. 



A System of Recording Cidtures of Bac- 

 teria Genealogically for Laboratory Pur- 

 poses: Burt Ransom Rickards, S.B., 

 Boston Board of Health Bacteriological 

 Laboratory. 



The writer applies to the recording of all 

 individual tube cultures of bacteria and 

 the data relating to them a modification of 

 the Dewey Decimal System under card cat- 

 alogue entries to correspond. Each species 

 is known by some whole number in the 

 hundreds (or thousands if a great many 

 cultures of one species are to be dealt 

 with). Thus: 



B. coli = 100, 

 B. typU=200, 



B. diphtherice=:300, 

 B. mallei^iOO. 



Individual specimens of any one species 

 are numbered in the order of their isola- 



