A Discussion of Some of the Factors Causing Variable Results with Flagella Stains

Most flagella stains would probably give more consistent results if they were of stable composition and more was known of the factors influencing the mechanism of their action. Many of the mordants that have been recommended change rapidly, both chemically and physically, after preparation.

The reaction of some mordants, such as that of Loeffler, seems to be an important factor in their use. It is complicated, however, by temperature effects, oxidizing and reducing agents, the age of the bacterial cultures and variations in different species.

Users of flagella stains will probably always have to select or alter methods to suit the cultures to be stained. Any method which makes use of a minimum of complicated solutions and operations is most likely to give consistently good results.

No clearing or decolorizing agent tried changed poor preparations to good ones, but sometimes good ones can be improved by this treatment.     

Some Factors Causing Mortality among Female Minks during the Puerperium and Lactation Periods

The purpose of this study, in which the farm was used as the statistical unit, was to find factors affecting mink mortality under farm conditions. Mortality was hypothesised to be affected by factors including, among others, variables describing the amount (level) and variation in composition and quality of the feed. Other explanatory variables applied in the study included farm size and age. Factor analyses were performed for variables of feed composition and quality in order to condense the variable information and to facilitate the selection of explanatory variables. This report presents a preliminary regression model for female mink mortality factors describing feed level and variation, and farm size, as explanatory variables. The regression model emphasized among other factors the importance of a constant albumin quality and a constant energy level.     

Some Factors Causing Variability in 1,2-Dibromo-3-Chloropropane Concentrations in Soil

Relative to nematicides with greater fuming capabilities, 1,2-dibromo-3-chloropropane (DBCP) moved nonuniformly through soil. DBCP concentrations in soil were reduced by low soil temperature and the presence of lime or roots within the soil profile, Applications by either water or chisel injection provided DBCP movement to 120 cm and below. Concentrations were least persistent in the upper 15 cm of the field surface and in one situation where application was not followed by irrigation. Values for Henry''s Constant are reported for DBCP at a range of solution temperatures. Certain advantages and disadvantages of soil atmosphere sampling of DBCP are discussed.     

A Method for the Staining of Bacterial Flagella

A modification of the Loeffler method of staining bacterial flagella is proposed. The chief points of the modification are: The cultures are inoculated into distilled water after two successive daily transfers on agar slants, and the distilled water cultures are incubated at optimum temperature for from 48 to 72 hours. The mordant (tannic acid, ferrous sulphate, basic fuchsin) is allowed to stand 18 to 24 hours before use, and then cleared by centrifuging or filtering. An anilin water fuchsin is used as a stain. No heat is used for either mordanting or staining; but both mordant and stain are allowed to act on the preparation for 15 minutes. The writer finds the method admirably adapted for use in class work, where nearly 100 per cent success has been obtained except in the case of some three or four species of bacteria that are especially difficult to stain.     

Progress in the Standardization of Stains Certain Less Commonly Used Stains

The Commission must acknowledge the assistance recently given by two commercial concerns in developing two new products, namely, a pure type of hematein and a special grade of acid fuchsin.     

An Evaluation of Some Aniline Dyes as Nuclear Stains in Trichrome Procedures

A comparison of the utility of gallocyanin, gallamine blue, celestine blue B and acid alizarin blue BB as nuclear stains for material to be counterstained by the van Gieson, Kornhauser, Gomori and Masson technics has been made. With all these nuclear stains except gallocyanin there were definite deficiencies. However, gallocyanin routinely has given excellent results and can be highly recommended. This dye is not specific for nucleic acids but rather stains some material with much the same spatial distribution in the cell as the nucleic acids.