86 



Metalnikoff (S.). Sur ia Digestion des Bacilles tuberculeux dans 

 le Corps des Chenilles des Mites des Abeilles {Galleria mellonella). — 

 C. R. Soc. Biol., Paris, Ixxxiii, no. 8, 28th February 1920, 

 pp. 214-215. 



It has been shown that tubercle bacilli are rapidly phagocytised by 

 leucocytes in the caterpillars of Galleria mellonella (bee moth) [R.A.E., 

 A, viii, 163]. To understand the later developments, examinations 

 have been made that show that the bulk of the bacilli injected are in 

 the centre of large and small capsules formed by groups of leucocytes. 

 The complete destruction of the baciUi takes place in these, and they 

 are gradually transformed into a brownish-black mass. It is easy to 

 distinguish all the intermediate stages between a normal bacillus that 

 can be stained by Ziehl and bacilh that have been digested and turned 

 into pigment. When the caterpillars have been injected with great 

 numbers of bacilli, often in solid masses, digestion proceeds much more 

 slowly, so that some days after injection isolated tubercle bacilli may 

 be found together with large masses transformed into pigment. This 

 explains why guinea-pigs injected with extracts taken from larvae after 

 eight hours' inoculation have acquired tuberculosis [loc. ciL], but does 

 not by any means disprove the rapid digestion of the tubercle bacilh. 



It is clearly proved, therefore, that the caterpillars possess an 

 extraordinary immunity against the tubercle bacillus and that this 

 immunity is due to certain ferments in the bodies of the phagocytes. 

 All attempts to isolate these ferments and use them as a remedy have 

 as yet been unsuccessful. 



Paillot (A.). L'Immunite acquise chez les Insectes.— C R. Soc. 

 Biol, Paris, Ixxxiii, no. 9, 6th March 1920, pp. 278-280. 



While it is admitted that invertebrates, as well as vertebrates, can 

 be immunised against infection by microbes, no decisive proof of this 

 has been obtained, and the existence of anti-bodies hke those found 

 in the blood of vertebrates is still problematical. In the case of insects 

 the author has not been able to confirm the conclusions of Canta- 

 cuzene (who showed that invertebrates, especially marine Crustacea, 

 could elaborate anti -bodies), bvit he has seen cases of natural 

 immunity exclusively due to the action of anti-bodies in the blood 

 [R.A.E., A, vii, 486], and a case of acquired immunity is here described. 



When caterpillars of Agrotis are inoculated with an emulsion of 

 Bacillus melolonthae non-liquefaciens of recent culture, fatal septi- 

 caemia rapidly supervenes ; the only other reaction is a shght 

 phagocytosis. If, however, a culture two or three months old is used 

 the caterpillars successfully resist inoculation, and a further inoculation 

 made 24 hours or even several days after the first, with a fresh culture, 

 does not produce fatal septicaemia. Regular examinations of the lilood 

 show that after about 10 minutes a certain number of the bacilh 

 transform into granules ; this process extends gradually to all the 

 free bacilh. While the reaction is going on, the micronucleocytes 

 envelop the intact microbes and the granules, but the normal, 

 enveloped microbes do not transform into granules in the protoplasm, 

 and this indicates that the anti-body or bodies in the blood do not 



