358 



SCIENCE. 



[Vol. XVII. No. 438 



temperature being favorable — that some multiply in twenty min- 

 utes, others in thii-ty minutes, and others in forty minutes. 



Staphylococcus aureus, which in its growth produces a peculiar 

 golden-colored filament, grows with great rapidity when sown in 

 a medium like faintly alkaline broth at a temperature of 37° C. 

 Into a sterile broth tube a definite number of organisms are put, 

 say eight cocci per cubic centimetre. If placed in an incubator 

 for twenty-four hours at 37° C, and then counted, it is found that 

 1 cubic centimetre contains 640,000; that is to say, one organism 

 has multiplied eighty thousand-fold in the first twenty-four hours. 

 It would not be expected that the same rate would obtain in the 

 second twenty-four hours, because the material had been used up. 

 After forty-eight hours' growth the counting yielded 248,000,000 

 per cubic centimetre; that is, only four hundred-fold. In seventy- 

 two hours it was found that there were 1,184,000,000 per cubic 

 centimetre ; that is to say, during the last day each had multiplied 

 only five-fold. As the material is used up the rate of multiplica- 

 tion decreases. 



Another instance of the rapidity of growth was given. A rabbit 

 was inoculated subcutaneously with 20,000 bacilli of fowl cholera, 

 and died in twenty-four hours. It was found that 15,150,000 mi- 

 crobes were contained in one cubic centimetre of the blood of the 

 animal. The whole of the blood contained twelve hundred mil- 

 lions, showing that each bacillus in twenty-four hours had multi- 

 plied sixty thousand times. Those organisms which have their 

 habitat in ordinary temperatures grow very rapidly. Professor 

 Ferdinand Cohn was the first to study the rate of multiplication 

 on the hay bacillus. He calculated that in two days the number 

 of these would be so great that the whole Atlantic Ocean would 

 be densely peopled by them if there was sufficient nutriment, 

 which, fortunately, there is not, and therefore many of them had 

 to go to the wall. 



By the motility of bacteria is understood active locomotion. 

 They spin round, they dart to and fro, and pass rapidly over the 

 field of the mici'oscope, and that is on account of their possessing 

 one, two, three, or even a multitude of fine hairs. The organism 

 of typhoid fever possesses several of these Jtapellce. It has been 

 shown that for retaining this motility a plentiful supply of iOxygen 

 is required. If, in a chamber, at one end oxygen is supplied, and 

 at the other nitrogen or hydrogen gas, the organisms will all move 

 towards the end where the oxygen is. If the oxygen is replaced 

 by nitrogen or hydrogen the movement gradually ceases. If 

 water is covered with a scum, it is most probably a motile bacillus 

 which grows in the fluid, and is driven to the surface, where it 

 can derive the best supply of oxygen. In many cases the motility 

 of the organisms is interfered with by their own chemical prod- 

 ucts. 



Within certain of these organisms, but not in all, are formed 

 pecuUar corpuscles, which bear the same relation to the organisms 

 as the seed does to the plant. This spore formation is almost en- 

 tirely limited to the order of bacilli, and in this group there are 

 very many species which do not possess this power. In a number 

 of different species of bacilli, some of which are capable of form- 

 ing spores and others not, those which have this power may look 

 on very quietly, while those that do not will exhaust all the nutri- 

 tive material present, growth and multiplication will then cease, 

 and they will gradually die away. Those which form spores have 

 a much better chance of bringing forth new generations than the 

 others. 



When organisms do not find suitable materials for their growth, 

 certain changes are brought about called "involution changes." 

 When the bacillus ceases to possess that high degree of vitality 

 that the normal typical bacillus possesses, it gradually undergoes 

 changes which lead to its death. Illustrations were given of what 

 had been described as involution changes, but which were not so. 

 For instance, tubercle bacilli grown under not very favorable con- 

 ditions may be swollen, and others may appear branched. Some 

 observers took these changes to indicate the death of the organ- 

 ism, but the lecturer was not quite sure that such were "involu- 

 tion changes." 



In aU these considerations, particularly in reference to the for- 

 mation of spores, there were a number of facts of very considera- 

 ble practical importance. The germination of those organisms 



which form spores takes place on the same principles as the ger- 

 mination of the spores in the higher fungi. The envelope is 

 broken, the protoplasm contained within it shoots out in the shape 

 of a rod, which when it is fully formed elongates, divides, and 

 multiplies, as in the case of the parent. In this way one bacillus, 

 by repeated multiplication, forms a new crop. When these have 

 reached a certain phase of development they again form spores, 

 which go to start a new generation. These spores have a much 

 greater power of resistance than is possessed by the non-spoi-e- 

 bearing organisms, and can withstand high temperature, dryness, 

 and the influence of light, so much so that it has become almost a 

 recognized method of determining whether a particular species of 

 bacilli forms spores, by subjecting the suspected organism to a 

 temperature of 95° C. or 100" C. If they survive this exposure, 

 and if they survive drying, it may be taken as established that the 

 growth is spore- forming. 



HEALTH MATTERS. 



The Transmissibility of Hydrophobia from Man to Man. 

 The fact that no instance is on record of hydrophobia having 

 been transmitted from man to man has given rise to a doubt as to 

 whether the saliva of human beings suffering from the disease 

 possesses the same virulent properties as that of the dog 

 similarly affected. In not more than five or six of the ten 

 thousand patients treated at the Pasteur Institute was the 

 lesion due to bites inflicted by human beings, and it is evi- 

 dent that statistics bearing on so small a number of cases 

 are of no value one way or the other. It has, however, been 

 proved experimentally, says the Medical Press, that the saliva of 

 human beings having succumbed to hydrophobia produces the 

 disease in animals by inoculation, though the incubation period is 

 somewhat prolonged. It may, therefore, be taken as proved that 

 the disease may be transmitted in this way from man to man. 

 It is hardly possible as yet to affirm categorically the possi- 

 bility of curing hydrophobia after the characteristic symptoms 

 have made their appearance, but recent observations throw a 

 doubt on the incurability of the disease even under these circum- 

 stances. 



LETTERS TO THE EDITOR. 



•#* Correspondents are requested to be as brief as possible. The writer^s name 

 is in all cases required as proof of good faith. 



On request, twenty copies of the number containing his communication loill 

 be furnished free to any correspondent. 



The editor will be glad to publish any queries consonant with the character 

 of the journal. 



The Glacial Grooves on Kelley's Island to be Preserved. 



The world of science wiU rejoice that at last the most remarka- 

 ble of the glacial grooves on Kelley's Island is to be preserved as 

 an object-lesson to future generations forever. 



Many of the citizens of Cleveland will remember that when, in 

 1888, the American Association for the Advancement of Science 

 met in their city, an excursion was made to Put-in-Bay on the 

 steamer " City of Cleveland," and that, on the way, the boat 

 stopped at the dock of the Kelley's Island Lime and Transport 

 Company, on the north-east corner of the island, to give the men 

 of science an opportunity to see what thei'e was left of the won- 

 derful glacial grooves that have made that locality famous the 

 world over, A few minutes after the palatial steamer touched 

 the dock at the lime-kilns, the hundreds of expectant excursionists 

 might have been seen swarming around and over the great natural 

 wonder they had come to see, and inspecting it from every point 

 of view. They had come, they had seen, and they were conquered. 

 The expressions of astonishment and delight from the eminent 

 scientific men in the company (among whom were numbered Pro- 

 fessors Alexander and N. H. Winchell, Professor Cook of New 

 Jersey, Professor Morse of Boston, Major Powell of Washington, 

 Professor Spencer of Canada), as well as from the great number of 

 intelligent amateurs and others present, were of the most extrava- 

 gant character; and ardent desire was expressed on every hand 

 that measures might be taken for the preservation of the renowned 

 glacial phenomenon, concerning which all felt that the half had 



