No abstract

One rat in group I, one in group III, and two in group IV died within a few hours after the first intracranial injection and were discarded. One additional rat in each of the test groups I, II, and III died during the course of intraperitoneal injections after receiving 1,600, 2,000, and 5,200 units of penicillin, respectively, in addition to 1,000 units intracranially. These rats were placed in the icebox and were used in the brain passage phase of the experiment. The death of these animals was attributed to barbiturate poisoning, although brain injury may have been involved, especially in the early deaths.Two days after termination of the penicillin treatment, the brains of the 4 surviving, the 3 icebox-preserved test rats, and the 6 surviving control rats were removed, emulsified, and passed to fresh rats. Uniform (0.01 ml of 1:20 dil.) dark-field preparations of the tail blood of each of these passage rats were examined daily for 10 days. All 6 of the control passage animals became positive within 3 to 6 days, whereas the 7 test passage animals remained negative throughout the ten-day examination period.Thus it would appear that penicillin injected intracranially is capable of curing the brain involvement in experimental relapsing fever of the white rat. Mini-

In a previous publication (Ross et al., 1955), it was noted that during the course of infection with Salmonell pullorum, some of the free and bound amino acids of the blood and liver of chicks were reduced. The levels of arginine, methionine, glycine, and tryptophan were markedly decreased as compared to normal controls, or to chicks inoculated with an avirulent strain of the test organism. According to Almquist (1947), arginine, methionine, glycine, and tryptophan are esential to the nutrition of the chick, which is incapable of synthesizing them. Hence, they must be supplied in the diet. Since these four amino acids are depleted during the course of infection of the chick with S. pullorum, it became of interest to us to determine whether their introduction into the infected host could alter the course of the disease as well as affect survival time. METHODS The virulent strains of S. pullorum were supplied by the Communicable Dise Center, U. S.

The production of oversensitized antigens for use in diagnosis of Brucella infections has created a problem in the interpretation of agglutination tests. According to Huddleson,l the presence of dissolved agar in dilutions as high as 1-50,000 in the antigen can cause nonspecific agglutination of the organisms, Tallman2 employed cellophane sheets over Bordet-Gengou agar for the cultivation of Hemophilus pertussis with considerable success in ridding suspensions of blood cells and possibly of dissolved agar. Later, Moore and Mitchell3 suggested the use of a dialysing membrane layered over broth absorbed in cotton. Growth was obtained in this manner and used in the production of a less sensitive antigen. Harmsen and Iiolffl also employed cellophane as a dialysing membrane for growth of bacteria nourished by fluid on the opposite side. They pointed out that the membranes were impermeable to bacteria and virmes, but allowed passage of water and$ solutes, except those of very large molecular weight.The present paper is concerned with a cultural method designed to eliminate oversensitivity of rapid antigen by using a collodion dialysing m,embrane in con junction with agar plates as described.Method and Equipment. A BAI strain of Brucella abortus exhibiting normal agglutinability was employed throughout. The organisms were grown on a sterile collodion mem-1 Huddleson, I. Forrestbrane* superimposed on the surface of an agar plate, The collodion sheets were cut so as to give a circular sheet of approximately 130 cm in diameter to fit over a large Petri dish. Each sheet was layered between a piece of flat wrapping paper backed by cardboard in order to maintain the flatness of the membrane and sterilized! by autoclaving at 121" C, for 30 minutes.The medium used was Bacto-tryptose agar. To obtain larger areas of growth, the medium was poured into sterile 150 cm Petri dishes and allowed to solidify. The collodion membrane was then placed on the surface of the agar by using a pair of sterile forceps, flaming after each plating. A tendency for the membrane to curl was noted. This objectionable feature was rectified by allowing plates to stand inverted in the refrigerator for several hours after which time a smooth surface was obtained. Extreme caution was taken at the time of placing the membrane on the agar surfaces as possibilities for contamination during this procedure were very great.A 24 hour culture of BruceEla abortus was used. To this culture was added 5 ml of tryptose broth and the growth removed from *There are two types of collodion membrane that might be used. The first is covered with a fine coating of plastic film. This coating prevents the free passage of nutritional fluids through the membrane and thus must be removed before use. This can be done readily by boiling for several minutes in a 570 solution of bicarbonate.Commercial cellophane is permeated with oil, which renders it unsatisfactory. The other type of cellophane is that which is free from either a coating film or oil and readily permits free passage of...

No abstract