PROGKESS OF MICROSCOPICAL SCIENCE. 21 



ence ' as if it had been proved to exist. As to the close correspondence 

 in chemical composition, asserted to exist between man and apes, the 

 same remarks may be made. Such correspondence has yet to be 

 shown." 



Vitality of Disease Germs. — In a recent number w^e referred to 

 Dr. Grace Calvert's niunerous experiments on this subject. Since 

 they were made, Mr. H. B. Yardley writes as follows to the ' Chemical 

 News ' : — " Dr. Calvert (in jirevious numbers) in his pai:)er says, that at 

 400° germ life cannot exist, but I take it that his experiments were 

 conducted at 100°, 200°, 300°, 400°, 500°, and 600° Fahr. only, and that 

 the intermediate temperatures were not tried. If this is the case, it 

 might hai^pen that even at 330° Fahr. germ life would be destroyed, 

 which will consequently render disinfection by heat practicable. 

 Not having the time or apparatus to repeat Dr. Calvert's experiments 

 myself, I take the liberty of mentioning this." We may mention that 

 the letter was a projjos of a statement by Mr. Richard Weaver in a 

 former number of the Journal, that 350° is the highest heat that may 

 be used for disinfecting without destroying the fabrics. 



How to Destroy Disease Germs in Clothing. — In a letter to the 

 ' Chemical News,' Mr. G. E. Davis states his own experience on this 

 subject. A propos of Dr. Calvert's researches, he says he has devoted 

 a considerable portion of time to the study of disinfectants — in fact, 

 sanitary chemistry generally, and the fact struck him as soon as he 

 entered the field that the miasm was not destroyed by the heat of most 

 disinfecting chambers. In fact, in some, where the heat emjiloyed is 

 very low, owing to a badly-constructed oven, very little good can 

 accrue from the baking process alone. At the Sanatorium attached 

 to Eton College the beds from the scarlatina patients used to be baked 

 at rather a high temperature, but owing to scorchings having taken 

 place the temperature has been considerably reduced. The heat now 

 employed, if used alone, is, in his opinion, only just enough to warm 

 the disease germ and make it feel very comfortable. The heat cannot 

 be raised too high owing to its irregular working, the temperature 

 being sometimes 40° or 50° higher than the thermometer indicates. 

 In December, 1870, he found the heat was only got up to 120° Fahr., 

 but it was supposed to rise to 160° Fahr. He gave as his oi^inion 

 that the heat had very little action upon the disease germ, and 

 proposed placing a vessel containing carbolic acid mixed with an 

 equal volume of water in the hot chamber. He has now written to 

 know whether the system proposed by him has been fully carried out. 

 He finds that for the last nine months, when articles have been placed 

 in the disinfecting chamber, the heat has been averaging from 120° 

 Fahr. to 160° Fahr., and a vessel of dilute carbolic acid (1 to 1) has 

 been placed in the next compartment to the clothes. The vapour of 

 the phenol has been carried over by the combined effects of heat and 

 steam, and has saturated the clothing. This he considers a good 

 method, certainly better than baking alone, for ensuring complete 

 destruction of any lower organism. Previous to December, 1870, the 

 method of disinfecting the patients' linen before washing, was to 

 stcei) in solution of bleaching powder, but owing to the solution being 



