408 SUMMARY OF CURRENT RESEARCHES RELATING TO 



method is also of use in the' sterilization or pasteurization of different 

 organic liquids (e.g. milk), as no appreciable modification in their 

 characters and constituents is brought about. 



Thyroid and Supra-renal Glands as Bacterial Culture Media.* 

 C. J. Parhon and E. Savini have attempted to grow various organisms, 

 Bacillits antfvracis, II. tuberculosis, etc., on sterile thyroid gland substance. 

 The organ is cut in half-cylindrical pieces, which are placed in the kind 

 of test-tubes that are used for potato cultures. In growing the tubercle 

 bacillus it is necessary to impregnate the piece of tissue for some hours 

 with glycerinated (6 p.c.) physiological salt solution. 



On thyroid medium the anthrax bacillus grows quickly, but does not 

 form tangled filaments, as upon ordinary media. It shows a manifest 

 tendency to isolated growth, such growth appearing in L-, V-, U-, or 

 O-shaped forms. The medium has a pronounced bactericidal action, 

 numbers of the bacilli soon dying off, the number of survivors being 

 extremely reduced. Sporulation is delayed. 



The tubercle bacillus (human, bovine, or avian) cannot grow on 

 glycerinated thyroid gland, even after a stay of three or four weeks in 

 the incubator. The conclusion is arrived at that the thyroid gland 

 exerts an obvious action on the growth and vitality of the anthrax and 

 tubercle bacillus, and plays an important part in the complex mechanism 

 of immunity. 



Anthrax also grows well on supra-renal gland tissue, giving a shining 

 thick growth of a cafe-au-lait colour, which soon changes to chestnut. 

 Sometimes the colour of the culture is grey-violet. The bacilli exhibit 

 marked pleomorphism on this medium, and many dead individuals can 

 be discerned. The tubercle bacillus grows slowly and with difficulty on 

 glycerinated supra-renal gland. After several weeks a scanty growth 

 appears, the best development being with the avian type of the bacillus. 

 Microscopically, the bacilli are much altered, the interior of the organisms 

 containing one or many strongly-staining granules, which sometimes 

 show a bi-polar arrangement. 



(4) Staining and Injecting. 



Vital-staining with the Free Base of Neutral Red.f — A. M. 

 Przesmycki has employed the free base of neutral red in the vital-stain- 

 ing of the nucleus of certain Infusorian parasites, such as Opalina 

 ranarum, Balantidium entozoon, and Nyctotherus cordiformis, and finds 

 that this stain is much more rapid in its action than neutral red itself. 

 The free base is prepared as follows : to an aqueous solution of neutral 

 red (monochlorhydrate) is added ammonium hydrate until the com- 

 mencement of the formation of an orange-yellow flocculent precipitate. 

 The chloride of ammonia and ammonia in excess are eliminated by 

 filtration and washing in distilled water. The free base is left behind 

 on the filter-paper in orange-yellow crystals, which are then dried at 

 80-100° C. On drying, the crystals assume a deeper colour, which is 

 described as being between orange-red and blood-red. 



* C.R. Soc. Biol. Paris, lxxviii. (1915) pp. 161-3 and 163-5. 

 t C.R. Soc. Biol. Paris, lxxviii. (1915) pp. 169-71. 



