270 



NATURE 



[Fed. 3, 1876 



ten nearest the stove had given way to putrefaction. 

 Three of the rows most distant from the stove had yielded, 

 while here and there over the tray particular tubes were 

 singled out and smitten by the infection. Of the whole 

 tray of one hundred tubes, twenty-seven were either 

 muddy or cloudy on the nth. Thus, doubtless, in a con- 

 tagious atmosphere, are individuals successively struck 

 down. On the 12th all the tubes had given way, but the 

 differences in their contents were extraordinary. All of 

 them contained Bacteria, some few, others in swarms. 

 In some tubes they were slow and sickly in their motions, 

 in some apparently dead, while in others they darted 

 about with rampant vigour. These differences are to 

 be referred to changes in the germinal matter, for the 

 same infusion was presented everywhere to the air. Here 

 also we have a picture of what occurs during an epidemic, 

 the difference in number and energy of the Bacterial 

 swarms resembling the varying intensity of the disease. 

 It becomes obvious from these experiments that of two 

 individuals of the same population, exposed to a con- 

 tagious atmosphere, the one may be severely, the other 

 lightly attacked, though the two individuals may be as 

 identical as regards susceptibility as two samples of one 

 and the same mutton infusion. 



The author traces still further the parallelism of these 

 actions with the progress of infectious disease. The 

 Times of January 17 contained a remarkable letter on 

 Typhoid Fever signed " M.D.," in which occurs the fol- 

 lowing remarkable statement : — " In one part of it (Edin- 

 burgh), congregated together and inhabited by the lowest 

 of the population, there are, according to the Corporation 

 return for 1874, no less than 14,319 houses or dwellings — 

 many under one roof, on the ' flat ' system — in which 

 there are no house connections whatever with the street 

 sewers, and, consequently, no water-closets. To this 

 day, therefore, all the excrementitious and other refuse of 

 the inhabitants is collected in pails or pans, and remains 

 in their midst, generally in a partitioned-off corner of the 

 living room, until the next day, when it is taken down to 

 the streets and emptied into the Corporation carts. 

 Drunken and vicious though the population be, herded 

 together like sheep, and with the filth collected and kept 

 for twenty-four hours in their very midst, it is a remark- 

 able fact that typhoid fever and diphtheria are simply 

 unknown in these wretched hovels." 



This case has its analogue in the following experiment, 

 which is representative of a class. On Nov. 30 a quantity 

 of animal refuse, embracing beef, fish, rabbit, hare, was 

 placed in two large test-tubes opening into a protecting 

 chamber containing six tubes. On Dec. 13, when the 

 refuse was in a state of noisome putrefaction, infusions of 

 whiting, turnip, beef, and mutton were placed in the other 

 four tubes. They were boiled and abandoned to the 

 action of the foul " sewer gas " emitted by their two 

 putrid companions. On Christmas-day the four infusions 

 were limpid. The end of the pipette was then dipped 

 into one of the putrid tubes, and a quantity of matter 

 comparable in smallness to the pock-lymph held on the 

 point of a lancet was transferred to the turnip. Its clear- 

 ness was not sensibly affected at the time ; but on the 

 26th it was turbid throughout. On the 27th a speck from 

 the infected turnip was transferred to the whiting ; on the 

 28th disease had taken entire possession of the whiting. 

 To the present hour the beef and mutton tubes remain as 

 limpid as distilled water. Just as in the case of the living 

 men and women in Edinburgh, no amount of fetid gas 

 had the power of propagating the plague, as long as the 

 organisms which constitute the true contagium did not 

 gain access to the infusions. 



The universal prevalence of the germinal matter of 

 Bacteria in water has been demonstrated with the utmost 

 evidence by the experiments of Dr. Burdon Sanderson. 

 But the germs in water are in a very different condition, 

 as i-egards readiness for development, from those in air. In 



water they are thoroughly wetted, and ready, under the 

 proper conditions, to pass rapidly into the finished 

 organism. In air they are more or less desiccated, and 

 require a period of preparation more or less long to bring 

 them up to the starting-point of the water-germs. The 

 rapidity of development in an infusion infected by either 

 a speck of liquid containing Bacteria or a drop of water 

 is extraordinary. On Jan. 4 a thread of glass almost 

 as fine as a hair was dipped into a cloudy turnip in- 

 fusion, and the tip only of the glass fibre was introduced 

 into a large test-tube containing an infusion of red mullet. 

 Twelve hours subsequently the perfectly pellucid liquid 

 was cloudy throughout. A second test-tube containing 

 the same infusion was infected with a single drop of the 

 distilled water furnished by Messrs. Hopkin and Williams ; 

 twelve hours also sufficed to cloud the infusion thus 

 treated. Precisely the same experiments were made 

 with herring with the same result. At this season of the 

 year several days' exposure to the air are needed to produce 

 so great an effect. On Dec. 31 a strong turnip-infusion 

 was prepared by digesting thin slices in distilled water at a 

 temperature of 120° F. The infusion was divided between 

 four large test-tubes, in one of which it was left unboiled, 

 in another boiled for five minutes, in the two remain- 

 ing ones boiled, and after cooling infected with one drop 

 of beef-infusion containing Bacteria. In twenty-four 

 hours the unboiled tube and the two infected ones were 

 cloudy, the unboiled tube being the most turbid of the 

 three. The infusion here was peculiarly limpid after 

 digestion ; for turnip it was quite exceptional, and no 

 amount of searching with the microscope could reveal in 

 it at first the trace of a living Bacterium ; still germs were 

 there which, suitably nourished, passed in a single day 

 into Bacterial swarms without number. Five days have 

 not sufficed to produce an effect approximately equal to 

 this in the boiled tube, which was uninfected but exposed 

 to the common laboratory air. 



There cannot, moreover, be a doubt that the germs in 

 the air differ widely among themselves as regards pre- 

 paredness for development. Some are fresh, others old ; 

 some are dry, others moist. Infected by such germs the 

 same infusion would require different lengths of time to 

 develop Bacterial life. This remark applies to and 

 explains the different degrees of rapidity with which epi- 

 demic disease acts upon different people. In some the 

 hatching-period, if it may be called such, is long, in some 

 short, the differences depending upon the different degrees 

 of preparedness of the contagium. 



The author refers with particular satisfaction to the tm- 

 tiring patience, the admirable mechanical skill, the veracity 

 in thought, word, and deed displayed throughout this first 

 section of a large and complicated inquiry by his assistant, 

 Mr. John Cottrell, who was zealously aided by his junior 

 colleague, Mr. Frank Valter. 



Note. Jan. 31. — The notion that the^author limited 

 himself to temperatures of 60° and 70° Fahr. is an entire 

 misconception. But more of this anon. 



THE OCCURRENCE AND MANUFACTURE OF 

 FLINT SKIN-SCRAPERS FROM NEW JER- 

 SEY, U.S.A. 



A REMARKABLE feature of the common Indian 

 rehcs found in Central New Jersey is the very great 

 abundance of " skin-scrapers," as one form of stone im- 

 plements is everywhere known ; and the great care that 

 has evidently been bestowed upon them in the making 

 equally attracts the attention when a series of these im- 

 plements is examined. That a flint implement used m 

 the preparation of skins for clothing and tent-covermg 

 should require as much care in its manufacture as an 

 arrow-point, does not seem probable, and one would natu- 

 rally expect to find in a scraper simply a comparatively 



