208 Dr. A. Carpenter on 



opening, with the sequence of a severe attack of sickness. It 

 was the first case in which I was able to draw a distinct inference 

 as to cause and effect with which I came into contact, though I 

 was then satisfied that sewer gas did cause much illness in the 

 town. It was not long before this event that I had ventilated the 

 soil-pipes of my house, then in the Dingwall Eoad, the first ven- 

 tilator of the kind which was put up in Croydon, and by that 

 means, I think, saved my household from the invasion of typhoid- 

 fever, which affected my neighbours in every house m that road 

 right and left of me. From experiments carried out at that 

 time in various houses in Croydon, I was satisfied as to the 

 dangeroi^s character of sewer air when coming from unflushed, 

 unventilated sewers, and I determined to do my best to get the 

 Croydon system of sewers both flushed and ventilated. It was 

 not, however, until after the year 1865, with its distressing 

 events, that the local authorities would agree to adopt the prin- 

 ciple that every individual house should have its oavu protector 

 from the invasion of obnoxious gases. About that time the 

 experiments of the German scientist. Prof. Treber, of Dantzic, 

 who followed up Erzenburgh's discoveries, had made out the 

 connection between living organisms and disease, such as that 

 which produced splenic-fever in cattle, and relapsing-fever in 

 human beings. I began my own experiments on sewer air about 

 this time, and ti'ied to get some facts from personal observation 

 which should be worthy of a place in the literature of this 

 society. I had proved to my own satisfaction that potato Uight 

 was caused by a mould fungus (the Feronospora infestdiis), though 

 I did not, for one moment, claim to be the discoverer, but only 

 verified that which was suggested by others. I had learned that 

 dry rot resulted from another fungus (the Mcreleus laclirijmans). 

 I detailed my observations upon Peroiwspora inf('st(i)is in the 

 ' Times ' newspaper, with the result of drawing upon me the 

 anger of those who were working in the same field, perhaps in a 

 more conclusive measure than I did, but of whose work in that 

 particular field I was, like most other people at that time, quite 

 unaware. 



I followed out my observations upon sewer air by suspending 

 microscopic slides in those positions in which sewer air was dis- 

 tinctly found to make its exit. While I was so engaged I made 

 out that a number of Mr. Latham's charcoal baskets were inserted 

 into openings into which air sometimes entered. These baskets 

 had been provided to obviate the mischiefs from sewers by purify- 

 ing the air issuing from them by means of charcoal ; some 

 were openings for the admission of air rather than as exits. This 

 was especially the case with two or three openings at or near to 

 the Zion Nursery, which had been complained of as nuisances, 

 but which were conclusively proved to my own satisfaction to be 



