APPENDIX II. clxv 



much which used to be obscure. This theory explained how it 

 was that families might in certain cases live with fair health for 

 many years in the midst of great filth, while the dwellers in large 

 and apparently clean mansions were struck down by fever and diph- 

 theria. The filth which was found compatible with health was 

 always isolated filth, and until the germs of some specific disease were 

 introduced, this dirt was merely injurious, not poisonous. The 

 mansions which were apparently clean and yet fever-visited were 

 found to be those in which arrangements had been made for the re- 

 moval of offensive matter, which arrangements served also to distri- 

 bute poison germs from one house to another, from one room to another. 

 These mansions had long suckers extended from one to another 

 through the common sewer. Through these suckers, commonly 

 called " house drains," they imbibed every taint which any one house 

 in the system could supply. In fact, arrangements were too often 

 made which simply " laid on " poison to bedrooms just as gas or water 

 was laid on. He had known an intelligent person declare that no 

 harm could come up a certain pipe which ended in a bed-room, because 

 nothing offensive went down. That person had never realised the 

 fact that his pipe joined another pipe, which again joined a sewer, 

 which again, whenever there was an epidemic in the neighbourhood, 

 received innumerable poison germs ; and that, although nothing more 

 serious than scented soap and water went down, the germs of typhoid 

 fever might any day come up.' 



Professor Jenkin then proceeded to show how a house might be 

 absolutely cut off from all contamination from these sources of evil. 

 Then by means of large diagrams he showed the several systems of 

 pipes within a house. One system coloured red showed the pipes 

 that received foul matter. A system marked in blue showed pipes 

 used to ventilate this red system. The essential conditions of safety 

 in the internal fittings of a house it was inculcated were that no 

 air to be breathed, no w T ater to be drunk, should ever be contaminated 

 by connection with red or blue systems. Then in yellow were shown 

 the pipes which received dirty water, which was not necessarily foul. 

 Lastly a white system, which under no circumstances must ever touch 

 the ' red,' ' blue ' or ' yellow ' systems. Such a diagram recalled the 

 complicated anatomical drawings which illustrate the system of ar- 

 teries and veins in the human frame. Little wonder, then, that one 

 gentleman remarked, in perplexity, that he had not room in his house 

 for such a mass of pipes ; but they were already there, with other 

 pipes besides, all carefully hidden away, as in the human tenement 



