November 24, 1904] 



NA TURE 



It will be noted that the acrospores are comparatively uni- 

 form in size, and are wholly different from the extremely 

 -variable brown Fungus-germs produced from the Zooglcea 

 masses. 



What has just been illustrated is only one of the ways 

 in which Fungus-germs are produced in the pellicle from 

 Zooglcea masses. Anyone working at this subject will have 

 no difliculty in recognising many other modes in which 

 they originate. Sometimes the germs separate from the 

 Zooglcea masses as colourless units, and then take on an 

 -almost black colour before they begin to germinate, as in 

 the specimen shown in Fig. 12, which was taken on the 

 twelfth day from another pellicle on a hay infusion. 



I have frequently found that these heterogenetic Fungus- 

 germs are small ovoid bodies with one, or sometimes two, 

 nuclear particles such as may be seen in this case, and 

 also in some of the small brown units shown in Fig. q. 

 It is interesting, moreover, to find that the immediate pro- 

 ducts of segmentation which are about to develop into 

 flagellate Monads present, except for their spherical shape, 

 very similar characters, as may be seen by reference to 

 Fig. 5. A. 



It seems to me impossible to doubt that we have in the 

 processes which I have just described definite instances of 

 heterogenesis. The fact of the individualisation and the 

 seg[nentation of these Zooglcea masses cannot be denied. 

 It is plain, indeed, that from such aggregates of bacteria, 

 by common consent regarded as belonging to the vegetal 

 kingdom, we have the production of typical animal 

 organisms, and that, as I have said, no kin^Iiip bdwcen 





Fig. 12.— Heterogenetic Fungus germs becoming black and germinating 

 (X 500). 



bacteria and flagellate Monads has ever been recognised, or 

 even suspected, by the great majority of biologists ; and, 

 though it cannot be said that there is the same lack of 

 kinship between bacteria and Moulds, it can certainly be 

 said that the majority of biologists have never suspected 

 any such relation between these two forms of life as that 

 which has now been made known. 



I care little what names may be given to the bacteria, 

 though I am certain that many different varieties are prone 

 to form zoogloeal aggregates, and to go through one or 

 other variety of such changes as have just been described. 

 Being much interested with these processes that go on 

 in nature, and under more or less natural conditions, I have 

 been familiar with such phenomena for more than a gener- 

 ation ' ; but although they were made known so long ago 

 I am not aware that any bacteriologist in Europe, America 

 or elsewhere has ever repeated my observations. Bacterio- 

 logists to whom I have personally mentioned the subject 

 have, with only one exception, shown not the least desire 

 to examine specimens or to follow up the inquiry. They 

 seem wedded to their strict laboratory methods, and seem- 

 ingly prefer to have dealings with nothing but pure cultures 

 and sterilised media. I do not deny for a moment the 

 ' See Proceeilin^s of the Royal Society, 1872, vol. xx. p. 239. 

 NO. 1830, VOL. 71] 



enormous increase of knowledge, and the benefit which has 

 ,11 crued to the human race, trom their studies, but should 

 like to see a little more toleration displayed for those who 

 prefer to work in a different way, and strive to find out 

 what goes on under more natural conditions — undeterred 

 i)y the much talked of but much over-rated risk of " in- 

 fection." Assuredly, in the future, much of what is now 

 ascribed to " infection " will be differently regarded as the 

 " origin of species " by heterogenesis becomes more and 

 more known. 



If such processes as have just been described are con- 

 tinually going on in nature, but are not to be met with in 

 the laboratories of bacteriologists, it should make us hesi- 

 tate to repudiate a natural origin of living matter at the 

 present day simply because undoubted proof of its occur- 

 rence cannot be produced by laboratory experiments. If it 

 occurred in the past the law of Continuity would lead us 

 to expect that it has been continually occurring ever since, 

 and, as I said in my letter of November 10, " if the origin 

 of living matter takes place by the generation in suitable 

 fluids of the minutest particles gradually appearing from 

 the region of the invisible, such a process may be occurring 

 everywhere in nature's laboratories, though altogether 

 beyond the ken of man." H. Charlton Basthn. 



The Temperature of Meteorites. 



During the early part of the year igoi, when I was on 

 the staff of the Elswick Works, it occurred to me that it 

 would be useful and interesting if a connection could be 

 made between the conditions of the flight of artillery shells 

 and of meteorites. Later in the same year I made a pre- 

 liminary mathematical investigation into the matter, and as 

 a result a paper on the temperature of meteorites was sent 

 in as an essay to compete for the Smith prizes at Cambridge. 

 It was distinguished from other essays sent up in not re- 

 ceiving a prize. 



It has since remained a strong wish on my part some day 

 to work up the subject into a form fit for presentation to 

 a scientific society, but the pressure of other matters has 

 prevented this. In order, therefore, to preserve at least its 

 outlines, I give here a brief exposition of the premises, the 

 procedure, and the conclusions of the essay. 



Ordinary ballistic tables contain a wealth of information 

 as to the retardation experienced by projectiles of all sizes 

 and of one general shape. The shape of the shell is \vell 

 known. If the same rules can be made to fit the motion 

 of meteorites it is clear that the velocity at any time can 

 be obtained, and thence the loss of energy due to the 

 obstruction caused bv the air. This energy reappears as 

 heat, sound, electrical energy, chemical energy, &c. Of 

 these by far the most important is heat. Thus the con- 

 ditions under which a meteorite " heats up " can be ascer- 

 tained and if it be assumed that all the energy is so spent, 

 it is obvious that a superior limit to the resulting tempera- 

 ture may be obtained. One further point should, however, 

 be mentioned— a meteor which reaches the earth is called a 

 " meteorite," and the velocity necessary for this is such that 

 the time of passage through the material part of the earth s 

 atmosphere is so short, sav five seconds, that chemical burn- 

 ing will not, in general, introduce any sensible error. Such 

 error as might be introduced would be of the opposite sense 

 to radiation losses, themselves small for much the same 

 reason. , 



Meteorites may be of almost any shape. 1 have onlv 

 considered the shell shape, as it is the only one the flight of 

 which has been thoroughly investigated by exhaustive 

 experiment. ,, , ■ c 



According to Ingall's " Exterior Ballistics, the law of 

 the resistance of the air is a function of the velocity which, 

 for velocities above 1380 feet per second, is the velocity 

 squared. For meteoric problems, velocities less than this 

 are unimportant. Whether this simple law would hold 

 good for velocities of, say, 20 miles a second, or even the 

 7 miles a second which the earth can impose, is not known, 

 but for lack of a better it has been necessary to employ it. 



The next difficulty, and of difficulties there is no small 

 number, lies in the varying density of the air. A few 

 thousand feet is the upvvard limit of ordinary projectiles. 

 Even for howitzer shell the correction for rarefaction is so 

 slight that the simplest kind of correction is enough. For 



