SCIENCE. 



127 



order, which is indicated by panting breath and alter- 

 nately opening and closing its beak ; afterwards it be- 

 comes motionless, assumes the shape of a ball, refuses 

 food, and seems overcome with drowsiness, as is the case 

 with chickens affected with the disease. There is this 

 difference, however, that the chicken wakes up at the 

 least noise. This sleep lasts about four hours, after 

 which the chicken wakes up, looks as well as usual, eats 

 and cackles as if nothing had happened to it. 



I have repeated this experiment several times and have 

 always observed the same facts. Before injecting the 

 extract above mentioned, I took, in every case, the precau- 

 tion of injecting an extract of the pure chicken broth, 

 which does not cause analogous phenomena. 1 have, by 

 this means, acquired the conviction that, during the life 

 of the parasite, a narcotic is formed, and that it is this 

 narcotic which causes the morbid symptom of sleep so 

 characteristic of the disease which we are studying. 



By the acts of its nutrition the germ of the disease 

 causes grave disorders and brings on death. The germ, 

 being aerobian, absorbs during us life large quantities of 

 oxygen, and burns up many of the elements of its me- 

 dium of cultivation. This may be seen by comparing the 

 extract of the broth, before the development of the 

 germ, with the extract of the liquid in which the develop- 

 ment has taken place. Everything seems to show that it 

 is from the globules of the blood that the oxygen neces- 

 sary to its existence is derived by absorption through the 

 tissues. While the chickens are still alive, even when 

 death is still far off, their combs assume a violet tinge at 

 a time when the germ of disease is so little diffused 

 through the blood that it escapes microscopical examina- 

 tion. This species of asphyxia is one of the most curious 

 traits of the disease we are studying. Death is caused 

 by the grave disorders brought about by the develop- 

 ment of the parasite in its body, by peiicarditis, by serous 

 extravasations, by alterations of its internal organs, by 

 asphyxia, but the sleep characteristic of the disease is 

 caused by a product formed during the life of the germ, 

 which acts on the nervous centres. The independence 

 of these two effects in the symptoms of this disease is 

 further established by the fact that the extract from a 

 filtered cultivation of the germ acts as a narcotic on 

 chickens which have been submitted to the maximum de- 

 gree of vaccination.* 



These facts will, doubtless, be found worthy of the 

 meditations of pathologists. 



Although I have takeu already much of its time with 

 this subject, the Academy will allow me to call its atten- 

 tion to some other characteristics of the disease called 

 chicken cholera. We know that this disease is rapidly 

 fatal, particularly if caused by a direct inoculation of its 

 germ. It must then appear extraordinary that it some- 

 times presents itself in the chronic state, as in the case 

 of inoculated chickens : which, after being severely ill,, do 

 not die, but seem to get relatively better. They eat, how- 

 ever, very little ; they become anasmic, as shown in the 

 discoloration of their combs ; they continue to lose flesh, 

 and finally die, after lingering for weeks or months. This 

 fact would not be of primary importance if, at the death 

 of the chicken, the germ of the disease was not, in most 

 cases, found in its body, which conclusively proves that 

 the parasite has been present since the last inoculation, 

 always active, although in a mild form, for it brings on 

 death slowly. Doubtless, the germ was placed in some 

 vaccinated portion unfavorable to its cultivation. Vac- 

 cinnated chickens are most apt to present this form of 

 disease, which is of very rare occurrence. We might be 

 led to believe that, in this case, the virulent virus is 

 changed into the attenuated, but this would be an error. 

 In cases of this kind the virulence of the germ of the dis- 



* I should, however, try to isolate the narcotic, and see whether a suffic- 

 ient quantity could cause death , and whether, in this case, the internal dis- 

 orders would be the same as those of the disease itself. 



ease seems, on the contrary, to be aggravated. This may 

 be easily seen by cultivating it artificially, so as to sepa- 

 rate it from the blood, and inoculating it on fresh 

 chickens. 



Facts of this kind help us to understand the possibility 

 of those long incubations of virus, such as that of rabies, 

 for instance, which, after existing a long time in the body 

 in a state which may be called latent, suddenly manifest 

 their presence by the most marked virulence and by 

 death. Do not these facts also throw light on human 

 pathology ? 



Alas ! how often we see virulent diseases, such as scar- 

 latina, measles, typhoid fever, followed by serious dis- 

 orders of long duration, which are frequently incurable ? 

 The facts to which I have called attention are of the 

 same nature, only here we can put our finger on their 

 true cause. 



I will conclude by pointing out another peculiarity, 

 which is not less worthy of the attention of the medical 

 profession. 



In chickens in perfect health which have been thor- 

 oughly vaccinated there often occurs an abscess full of 

 pus on some portion ot the body, which does not seem to 

 have any injurious effect on the health of the animal. It 

 is a remarkable circumstance that this abscess is due to 

 the germ of chicken cholera, which remains in it as in a 

 closed vessel, and it cannot propagate, doubtless, because 

 the chicken has been vaccinated. This germ may be 

 withdrawn by artificial cultivation, or it may be directly 

 inoculated on fresh chickens, which it kills in the usual 

 manner after an abundant development. These facts re- 

 call the abcesses on guinea-pigs, which I have mentioned 

 in the first communication on this subject, and they fur- 

 nish a rational expiation of what happens in these ab- 

 cesses. In all likelihood the muscles of the guinea-pig 

 cultivate the germ more slowly and with greater difficulty 

 than those of chickens ; the disease is limited to an ab- 

 scess, and recovery becomes possible. 



I will now conclude this statement, as I have no wish 

 to wear out the patience of this Academy. This subject 

 is, however, so vast and so fruitful that I will ask its per- 

 mission to bring the subject before it again. I have other 

 observations to present than these. I will add those 

 which will present themselves in the investigations I am 

 now making. 



" We would give nothing to the public," said Lavoisier, 

 " if we waited until we reach the end of our researches, 

 as these become broader and more extended the farther we 

 advance." 



THE NEW CHEMISTRY. 



Lieut. -Col. W. A. Ross, who has done so much to ad- 

 vance our knowledge of blowpipe analysis, and whose 

 original chemical investigations are of the greatest inter- 

 est, in speaking of Prof. Cooke's " New Chemistry," indi- 

 cates as follows, that much more radical changes, at all 

 events as regards anhydrates, will shortly demand the 

 attention of philosophical chemists, in consequence of the 

 following facts : 



Fact i. 5mgrs. of pure caustic lime are carefully fused 

 into a uead ot pure boric acid before the blowpipe, the 

 bead boiled in distilled water, and the transparent cal- 

 cium borate ball thus extracted, weighed. The weight 

 will invariably be exactly 2omgrs. 



Fact 2. — The above-mentioned ball is now fused into 

 a second bead of boric acid, the transparency of which it 

 does not in the least degree affect, and when again boiled 

 out it has the same weight — viz., 2omgrs. 



FACT 3. — 5mgrs. of calcium hydrate are now fused into 

 a boric acid bead similarly to (i), when it is observed that 

 the borate ball formed is at first opaque white; then, as 

 it becomes transparent B B, that an enormous amount of 

 opalescent matter is emitted from the ball into the bead ; 

 and finally, that the extracted ball weighs only 1 5mgrs, 



