Polytechnic Association. 805 



animal and vegetable morphology. Its physiology is not less rich in 

 subjects for inquiry. Take, for example, the singular fact that yeast 

 will increase indefinitely when grown in the dark, in water containing 

 only tartrate of ammonia, a small per centage of mineral salts and 

 sugar. Out of these materials the Torulce will manufacture nitro- 

 genous protoplasm, cellulose and fatty matters, in any quantity, 

 although they are wholly deprived of those rays of the sun, the influ- 

 ence of which is essential to the growth of ordinary plants. There 

 has been a great deal of speculation lately, as to how the living 

 organisms buried beneath two or three thousand fathoms of water, 

 and therefore in all probability almost deprived of light, live. If any 

 of them possess the same power as yeast (and the same capacity for 

 living without light is exhibited by some other fungi), there would 

 seem to be no difficulty about the matter. 



Of the pathological bearings of the study of yeast and other such 

 organisms, I have spoken elsewhere. It is certain that, in some ani- 

 mals, devastating epidemics are caused by fungi of low order — simi- 

 lar to those of which Torula is a sort of offshoot. It is certain that 

 such diseases are propagated by contagion and infection, in just the 

 same way as ordinary contagious and infectious diseases are propa- 

 gated. Of course, it does not follow from this that all contagious and 

 infectious diseases are caused by organisms of as definite and inde- 

 pendent a character as the Torula; but, I think, it does follow 

 that it is prudent and wise to satisfy oneself, in each particular case, 

 that the " germ theory " cannot and will not explain the facts, before 

 having recourse to hopotheses which have no equal support from 

 analogy. 



Adjourned. 



February 16, 1872. 



Prof. S. D. Tillman, in the chair; Robert Weir, Esq., Secretary. 

 Blowing off Steam. 

 Mr. J. K. Fisher inquired how much water would be blown off 

 with the steam from a field boiler. 



Dr. P. H. Yan der Weyde — You may blow the boiler empty. 

 Mr. T. D. Stetson — It is a question of time. If you blow off 

 rapidly, the steam mixed with the water will throw the water out, 

 and that is what takes place in an explosion. If you blow off slowly, 

 you will leave the boiler nearly full. 



