Jantjaey 29, 1897.] 



SCIENCE. 



193 



■con, and yield, on treatment with water, me- 

 tallic hydroxides and silicon hydride. Metallic 

 borides are made in the same way and behave 

 similarly with water, excepting that boron hy- 

 dride is itself decomposed by water forming 

 boric acid. 



The metallic hydrides, or compounds of metals 

 with hydrogen, are but little known. The hy- 

 dride of lithium has been carefully studied by 

 Ountz, the hydrides of calcium, strontium and 

 barium and of some rarer metals by Winkler. 

 The hydrides are all stable at very high tem- 

 peratures, but are decomposed violently by 

 water, yielding metallic hydroxides and hydro- 

 gen. 



Spectrum analysis proves the existence of 

 hydrogen, carbon, and many metals, in the stars 

 and in the atmosphere of the sun, at tempera- 

 tures too high for water, ammonia and most 

 metal oxides to exist. It is highly probable that 

 the metals exist in the heavenly bodies at the 

 present time and formerly existed on the earth 

 when the earth was hot enough, in combination 

 with the elements mentioned above. A study 

 of the decomposition of these compounds with 

 water and with air, throws light on the chemical 

 changes and rearrangements occurring on the 

 cooling of a world ; for example, metallic hy- 

 drides cooled to a suflBcient temperature in pres- 

 ence of oxygen take fire and burn, forming me- 

 tallic oxides and water vapor ; the oxides form 

 hydroxides with the water. Carbides are broken 

 down by the water into hydroxides and hydro- 

 carbons. The hydrocarbons burn in oxygen to 

 form water and carbonic acid, which last com- 

 bines with the hydroxides to form water and 

 metallic carbonates. The ammonia necessary 

 for the beginnings of plant life could be fur- 

 nished by action of water on the nitrides. The 

 formation of silicates and borates would neces- 

 sarily occur in the same way as that of the car- 

 bonates. Thus we can by laboratory study form 

 -a clear picture of the genesis of the metallic 

 ■compounds now existing on the earth. 



' A Recently Discovered Property of the 

 Blood Serum in Animals immune from Certain 

 Diseases and its Application to the Diagnosis of 

 these Diseases in Human Beings, ' by Dr. Simon 

 Flexner. 



A significant advance has just been made in 



regard to the diagnosis of typhoid fever. The 

 basis of this advance is the so-called cholera re- 

 action of Pfeiflfer which, it may be recalled, was 

 introduced for the purpose of discriminating 

 between the vibrio of Asiatic cholera and certain 

 allied bacterial forms. PfeifFer found that the 

 blood serum of an animal rendered immune 

 from the cholera germ would, if admixed with 

 a pure culture of this germ and introduced into 

 the peritoneal cavity of a guinea pig, cause a 

 rapid dissolution of the micro-organisms, while 

 no effect was exerted upon other, although 

 closely allied, species. The same reaction can 

 be obtained with various other bacterial forms, 

 such as the diphtheria bacillus, typhoid bacillus, 

 cholera bacillus, etc. , provided the serum of ani- 

 mals immune from these organisms be substi- 

 stuted for the cholera serum. Thus it was 

 shown that the action of the immunized sera is 

 specific for a particular kind of bacterial proto- 

 plasm. The changes which are induced in 

 animals by exposing them to experimental in- 

 fection with the bacteria mentioned take place, 

 in a similar manner, in human beings who suffer 

 from the diseases caused by these micro-organ- 

 isms. In the course of typhoid fever, cholera 

 and diphtheria immunizing substances, before 

 absent, now appear in the blood and other fluids 

 of the body. 



It seems very natural to reverse the order of 

 applying the reaction mentioned and, instead of 

 using a specific immunized blood serum to de- 

 tect a particular kind of bacterium, to employ 

 a specific micro-organism in order to discover 

 the presence of the immunizing substances. 

 Proceeding upon this idea Widal, and after 

 him Griinbaum, suggested that in doubtful cases 

 of typhoid fever the blood of the patient might 

 be utilized for the purposes of diagnosis. The 

 method of making the tests are simple and 

 readily carried out. Widal recommends ad- 

 ding to a bouillon culture of the bacillus 

 typhosus about 1-lOth of its volume of the blood 

 serum from the suspicious case. If it is one of 

 typhoid fever the bacteria soon begin to run 

 together, foi-m clumps and gradually sink to 

 the bottom of the test tube in the form of a 

 sediment. A slight modification of this method 

 consists in using a mixture of blood serum and 

 bouillon iu the proportions mentioned, which 



