SCIENCE LETTER FROM PARIS. 349 



tion of raw meat is necessary; here duty suggests to ascertain Avell the origin of 

 such meat; in all other cases it is prudent to only eat meats suitably cooked, that 

 is, meat whose interior has been acted upon by a temperature of 150° or t6o°. 



The experiments of M. Pasteur are certainly setting not only the scientific 

 world thinking, but acting. By inoculating sheep with the virus specially pre- 

 pared, of the malady Charbon, he rendered them invulnerable to the disease. 

 Veterinary Professor Galtier, of Lyons, has followed up the idea in the case of 

 hydrophobia. He inoculated the veins of sheep with the virus of the madness, 

 and the animals never contracted the disease. In fact, this preventive act has 

 succeeded as ten sheep thus treated escaped the malady, while the ten others not 

 vaccinated, fell victims to the contagion. Can this vaccination be found appli- 

 cable to dogs, and render them proof against hydrophobia? 



The Electricity Exhibition has just opened, but everything is in admired 

 disorder. Several important exhibits have not even yet been installed. The 

 show is thus incomplete for scientific examination. It may be observed, how- 

 ever, that the exhibits are full of promise, and when their efficacity and utility 

 are tested, the progress of electric science must be benefitted. Perhaps opinion 

 is more interested in producing cheap light for domestic purposes, than in any 

 other immediate application of electricity. 



The German cavalry are not only being instructed how to destroy railways 

 and telegraphs, but to construct both. In case of war the cavalry would be at 

 once thrown forward in the enemy's country, each soldier is provided with dyna- 

 mite cartridges; he has only to place one between the rails and sleepers, apply a 

 simple firecord, and the railway is blocked. In the case of the telegraph wires, 

 they do not cut down the posts; that would require too much time, and would 

 render them useless when subsequently the enemy himself might want them ; the 

 soldiers have an arrangement by means of which the poles can be easily climbed 

 and the wires cut. 



Dr. Bouchardat has published an invaluable work on "Public and Private 

 Hygiene." Not an important every day question but is there examined profes- 

 sionally as well philosophically. His observations on the causes of infant mortal- 

 ity are very interesting. His counsels how to arrive at a reasonable advanced 

 age are practical ; he examines ably the delicate questions of consanguinity and 

 prostitution ; he deals with the hygiene of each profession ; what is special for the 

 soldier,- the sailor, the miner, etc. That portion of the work dealing with public 

 hygiene is most valuable; it comprehends all that refers to the soil of large cities, 

 the distribution of gas, pits, sewers, hospitals, schools, private houses, etc., heat- 

 ing, ventilation, epidemics, etc. The Doctor treats the question of the progress of 

 the French population and its connection with the price of food. He shows that if 

 France is behind other nations in the matter of births, she surpasses them in 

 point of average duration of life being longer, that is to say, the mean age of 



