152 



NATURE 



[June i8, 1903 



the lion runs to his prey with his nose to the ground, and 

 the action of the bloodhound is valuable on account of his 

 line scent. It seems with mind as mere knower and non- 

 manipulator of action these performances could not be put 

 through. A. Bowman. 



144 Well Street, Hackney, May 26. 



Musical Sands. 



May I record the discovery of musical sands at places 

 along the shore between Ramsgate and Kingsgate. The 

 sand occurs in small patches close to the chalk cliffs, the 

 largest patch being found at Joss Gap. In composi- 

 tion the sand is very similar to that of Studland Bay, but 

 the individual grains are more polished, and the proportion 

 of denser minerals far higher. Of course, the sand can 

 •only be experimented upon when it has been uncovered by 

 the sea for a sufficient length of time to enable it to 

 "become dry, and it gives remarkable results when tested 

 in the ordinary way — especially when placed in a china 

 vessel and struck with a wooden plunger. 



June 8. Cecil Carus-Wilson. 



THE STUDY OF BACTERIAL TOXINS. 



THE study of the toxins produced by bacteria is 

 one of the most important branches of bacteri- 

 ological research. The solution of some of the main 

 problems of immunity and disease depends upon the 

 knowledge that can be gained with reference to the 

 nature of the bacterial toxins and their mode of action 

 upon the animal body. 



The methods introduced by Pasteur, Koch, and 

 other observers have rendered it possible to detect and 

 to isolate the specific agents in a number of infective 

 processes. The number of infective diseases that have 

 been definitely associated with the action of bacteria is 

 considerable, e.g. tuberculosis, cholera, diphtheria, 

 typhoid fever, &c. 



It was natural that the earliest attempts to prevent 

 the invasion of the animal body by these micro- 

 parasites should be based more or less on the prin- 

 <:iples of Jennerian vaccination. An attenuated virus, 

 for example, was taken and used directly as a vaccine 

 in order to produce, if possible, an active immunity to 

 the disease in question. This system of protective 

 inoculation was tested in a number of diseases, and 

 ■notably in infective diseases of the lower animals. The 

 anthrax vaccine employed for the protection of cattle 

 and sheep is a typical example of such immunising 

 methods, whilst in recent years analogous methods of 

 protective inoculation have been extensively used in 

 certain diseases of man. 



The study of the microparasites associated with 

 diphtheria and tetanus showed that organisms of this 

 type possessed not merely infective but likewise marked 

 toxic properties. It was further established that these 

 toxic properties were the determining factors in the 

 production of the graver symptoms in cases of diph- 

 theria and tetanus. It therefore became apparent that 

 in diseases of this order, the point of cardinal import- 

 ance was to combat, if possible, the toxins produced in 

 their course. The laboratory experiments made with 

 the diphtheria and tetanus organisms demonstrated 

 that the poisons were soluble products of the bacterial 

 cells in question, and were excreted into the nutrient 

 fluids in which they had been cultivated. These toxins 

 were proved to be of a specific nature, as they repro- 

 duced the essential general symptoms of the diseases. 



Diphtheria and tetanus are therefore intoxications 

 of the body, due to the action of specific soluble poisons 

 produced by the parasites at the seat of infection. The 

 toxins, on being introduced into suitable animals 

 in carefully regulated doses, produced an active im- 

 rnunisation of the animals characterised by the forma- 

 tion in their blood of anti-bodies as regards the toxins 



NO. T755, '^OL 68] 



in question — in other words, antitoxins resulted. The 

 antitoxic serum, when added to the toxin in vitro, 

 robbed the toxin of its poisonous properties, and, prob- 

 ably in virtue of some chemical combination between 

 toxin and antitoxin, a neutral mixture resulted. The 

 serum containing these specific anti-bodies, on intro- 

 duction into other animals, conferred on them a passive 

 immunity. They were protected against the action of 

 the toxin in question, and, most important of all, the 

 serum was efficacious in the case of an already existing 

 intoxication — it possessed curative as well as protective 

 properties. If a large animal, such as a horse, vvas 

 actively immunised by injection of the soluble toxins, 

 considerable quantities of these antitoxic substances 

 were formed and accumulated in its blood and blood- 

 serum. In. this way the serum of an animal highly 

 charged with antitoxins became a valuable and in- 

 nocuous vehicle for the introduction of these preventive 

 and curative substances into the human system. The 

 natural defensive forces of the body were thereby re- 

 inforced, and in the right direction. This method of 

 serum therapeutics has had brilliant results in the case 

 of diphtheria, and has been demonstrated to be a 

 feasible therapeutic method in the case of tetanus. 

 These maladies belong to the group of intoxicative 

 diseases. There remamed, on the other hand, a large 

 number of diseases in which a general multiplication 

 of the microorganisms in their host appeared to be 

 the salient feature. It has been usual to call these, in 

 contradistinction to the former, infective diseases. The 

 successful results in the case of diphtheria led to the 

 extensive study on similar lines of infective organisms 

 generally. A systematic search was made for soluble 

 bacterial poisons, as their detection would be likely to 

 lead to valuable additions to antitoxic serum 

 therapeutics. 



The researches in this direction met with unexpected 

 difficulties and disappointments. The results obtained 

 in the case of diphtheria and tetanus were not found 

 to be of general application. Each organism had 

 therefore to be taken on its own merits, and indi- 

 vidually studied. It speedily became apparent that, as 

 regards a considerable number of infective agents, the 

 conditions were not the same. On cultivation in fluid 

 media no distinct evidence of the production of soluble 

 poisons could be obtained, or, if present, they were so 

 in an inappreciable amount. The attempts, therefore, 

 to produce antitoxins by the injection of such culture 

 fluids into animals did not promise to be of much prac- 

 tical value. This, as a matter of fact, has proved to 

 be the case; the various serums prepared were found 

 to possess little or no curative value. Many infective 

 organisms did not apparently produce their injurious 

 effects through the agency of soluble toxins, and conse- 

 quently curative methods based on the assumption re- 

 sulted in failure. Research was thrown back once 

 more upon the living infective agents, and the possi- 

 bilities there might be of protecting the body directly 

 against their invasions, or, in other words, of produc- 

 ing not a poison but a bacterial immunity. Bac- 

 tericidal substances were found to be present in the blood 

 of individuals who had passed through an attack of 

 certain infective diseases, and the bactericidal action 

 was specific as regards the infective agent in each case. 

 For example, the blood of a patient recovering from 

 typhoid fever is bactericidal to the typhoid organism. 

 In the absence of soluble immunising products, there 

 was a strong presumption that these substances were 

 to be sought for within the bodies of the bacteria. The 

 bacteria in that .case, if injected directly into the 

 system, would tend to produce an active immunisation 

 of the body, and would reinforce the bactericidal pro- 

 perties of the tissues in specific directions. The method 

 most generally favoured for this purpose was the in- 



