DISINFECTANT 41 



protection against some miasmas. Salts, or compounds of acids with bases, are 

 valuable antiseptics ; some of them are also disinfectants, that is, they remove the 

 state of putrefaction after it has begun. An antiseptic prevents it, but does not ne- 

 cessarily remove it. Common salt is well known as a preserver of flesh; nitrate 

 of potash, or saltpetre, is a still more powerful one. _ Some of these $ salts act by 

 removing the water. Meat, treated -with these salts, gives out its moisture, and a 

 strong solution of brine is formed. Chloride of calcium prevents, to some extent, the 

 putrefaction of wood. Alum, or the sulphate of alumina, is not a very efficient pre- 

 server ; but chloride of aluminium seems to have been found more valuable. It is 

 sometimes injected into animals by the carotid artery and jugular vein. Meat, usually 

 keeps a fortnight : if well packed, cleaned, and washed with a solution of chloride of 

 aluminium, it will keep three months. This salt is sold as chloralum. 



But in reality the salts of the heavier metals are of more activity as disinfectants. 

 It has been supposed that their efficiency arose from their inclination to ^unite with 

 sulphur and phosphorus, and there is no doubt that this is one of their valuable 

 properties, by which they are capable of removing a large portion of the impure smell 

 of bodies ; but they have also an inclination to combine with organic substances, and 

 by this means they prevent them from undergoing the changes to which they are most 

 prone. The actual relative value of solutions it is not easy to tell. Most experiments 

 have been made on solutions not sufficiently definite in quantity. Salts of mercury 

 have been found highly antiseptic. Such a salt is used for preserving wood ; the 

 process is known as that of Kyan's, or kyanising. A solution of corrosive sublimate, 

 containing about 1 per cent, of the salt, is pressed into the wood either by a forcing 

 pump or by means of a vacuum. The albumen is the substance most apt to go into 

 putrefaction, and when in that condition it conveys the action to the wood. It is no 

 doubt by its action on the albumen that the mercury chiefly acts. Thin pieces^ of 

 pine wood, saturated for four weeks in a solution of 1 to 25 water, with the following 

 salts, were found, after two years, to be preserved in this order : 1. Wood alone, 

 brown and crumbling, 2. Akim, like No. 1. 3. Sulphate of manganese, like 1. 4. 

 Chloride of zinc, like 1. 5. Nitrate of lead, somewhat firmer. 6. Sulphate of copper, 

 less brown, firm. 7. Corrosive sublimate, reddish yellow and still firmer. In an 

 experiment, in which linen was buried with similar salts, the linen was quite con- 

 sumed, even the specimen with corrosive sublimate. Other experiments showed salts 

 of copper and mercury to protect best. Gmelin. 



Nevertheless, all these metallic salts are found true preservers under other condi- 

 tions. Chloride of manganese, a substance frequently thrown away, may be used, as 

 Gay-Lussac and Mr. Young have shown, with great advantage, and Mr. Boucherie has 

 shown the value of the acetate of iron. Mr. Boucherie's process is very peculiar. 

 He feeds the tree, when living, with the acetate of iron, by pouring it into a trough 

 dug around the root. The tree, when cut down, has its pores filled with the salt, and 

 the albumen in the sap is prevented from decomposing. For preservation of vegetable 

 and animal substances, see PUTREFACTION, PREVENTION or. 



The chloride of zinc of Sir William Burnett is also a valuable disinfectant, and has 

 more power than it would seem to possess from the experiments quoted above. 

 Wood, cords, and canvas have been preserved by it under water for many years. It 

 has the advantage also of being so soluble as to take up less room than most other 

 salts, although liquids generally are inconvenient as disinfectants in many places. 



Nitrate of lead is a disinfectant of a similar kind ; it lays hold of sulphur and 

 organic compounds. All these metals are too expensive for general use, and can only 

 be applied to the preservation of valuable materials. Even iron is expensive as a 

 disinfectant for materials to be thrown on the fields as manure. All are apt to be 

 very acid, a state to be avoided in a disinfectant, unless when it is applied to sub- 

 stances in a very dilute state, or in an active putrid state, and giving out ammonia. 

 E.A.S. See Dr. Angus Smith's Tables, pp. 45 to 47. 



This subject is further developed by the writer in his report to the Cattle Plague 

 Commission, 1866 ; and in 'Disinfectants:' Edmondston and Douglas, 1869. 



The importance of this subject appears to give considerable prominence to the 

 report made to Her Majesty's Commissioners on the Cattle Plague by Mr. Wm. 

 Crookes, F.K.S. We therefore select the more important portions. ^Referring espe- 

 cially to the Cattle Plague, Mr. Crookes says : 



' The specific disease-producing particles must, moreover, be organised, and possess 

 vitality; they must partake of the nature of virus rather than of poison.' 1 No poison 

 yet known to chemists can approach, even in a faint degree, the tremendous energy 

 of the active agent of infectious diseases. A poison may be organic, but it is not 

 organised. It may kill with far greater rapidity than the virus of infection, but, 



1 The words virus and poison are generally regarded as synonymous. It would be more convenient, 

 and would tend to promote accuracy of thought, were the distinction here made generally adopted. 



