ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 157 



preparation in a solution of some blue dye. The red spores do not take 

 up the blue pigment at all, while everything else is stained deeply blue. 



Staining- Lepra and Tubercle Bacilli.* — Dr. F. Wesener makes 

 another reply to Prof. Baumgartner's criticisms on the methods for dis- 

 tinguishing between leprosy and tubercle bacilli. Throughout the con- 

 troversy, no new facts have been adduced, and the gist of the whole 

 seems to be that the one learned stainer prefers bis own method to that 

 of the otber. They both seem to agree that tubercle, like leprosy 

 bacilli, can be stained with simple solutions of fuchsin and methyl- 

 violet ; that there are, however, certain gradual differences between 

 them, the leprosy bacilli taking up the stain somewhat more easily than 

 the tubercle bacilli. Dr. Wesener distinguishes his position from that 

 of Baumgartner by insisting that these gradual differences are very 

 fluctuating, and not always constant, and on this ground that they are 

 insufficient for a reliable diagnosis : the two methods given by Baum- 

 gartner for sections are specially unreliable. 



As both these learned dyers have admitted that other data besides 

 those of various stains (in so many words, it must be known beforehand 

 which is tubercle and which leprosy tissue) are necessary for a certain 

 diagnosis, it must be acknowleged that the main point in the con- 

 troversy is one which requires special mental acuteness for its compre- 

 hension. 



Specificness of the Tubercle Bacillus Stain.j — It is well known 

 that Bienstock and Gottstein demonstrated the fact that certain non- 

 pathogenic bacilli which stain in the ordinary way with anilin dyes could 

 be so altered that they were able to be stained in the same way as tubercle 

 bacillus. To effect this they were bred in agar-gelatin medium, to which 

 about 20 per cent, of fat was added. Dr. A. W. Grigorjew has now 

 tested Bienstock's conclusion, according to which tubercle bacilli owe 

 their peculiar staining property to an investment of fatty matter, which 

 prevents the decolorizing action of acids. The author cultivated in fatty 

 media (1-20 per cent.) Bacillus antliracis, B. subtilis, Clostridium buty- 

 ricum, Bacterium termo, Staphylococcus aureus, and S. alius. All these 

 cultivations gave similar results. Bacteria lying in the fat stained as 

 tubercle bacilli ; those above or in islets free from fat stained in the 

 usual way. Again, if the former class were acted on by potash, alcohol, 

 or ether, their power of assuming the specific stain vanished, and they 

 coloured in the usual way. The author further points to the significance 

 which the mixing of a little fat with the bacteria on the cover-glass has. 

 In this case the specific nature of the stain is lost. In this way it is even 

 possible to impart the specific tubercle stain to a streak of albumen, and 

 the author concludes that his experiments justify him in disbelieving 

 Bienstock's explanation, and in supporting the existing theory as to the 

 staining of tubercle bacilli. 



New Staining Fluid. $ — Mr. J. W. Boosevelt recommends an iron 

 stain, consisting of 20 drops of a saturated solution of iron sulphate, 



* Centrall.l. f. Bacterid, u. Parasiteuk., ii. (1887) pp. 131-5. 



t Ruskaja Mediziua, 1886, Nos. 42 and 43. Cf. Zeitschr. f. Wiss. Mikr., iv. (1887) 

 pp. 251-2. 



t New York Patholog. Soc, 9th March, 1887. Of. Medical Record, ii. (1887) 

 p. 84. 



