INDUSTRIAL PROGRESS DURING THE YEAR 1873. Ixxxiii 



fered to remain at rest, only to be revived by several English 

 writers, who dispute several alleged facts stated by Bastian, 

 and Mr. E. Ray Lankester seems quite positive that Mr. Bas- 

 tian is incorrect in several of his observations. In this con- 

 nection certain observations published in the Monthly Mi- 

 croscopical Journal have some significance. Messrs. Dallin- 

 ger and Drysdale studied a cercomonad, or infusorial being, 

 with an oval body, and provided with two actively moving 

 flagella, or lash-like filaments, at one end. This was the ma- 

 ture form ; while other forms, some differing in size and 

 shape, and with one flagellum at each end, others amoeboid, 

 with or without a flagellum, and still others cyst- like, and 

 smooth and globular, occurred. All these forms were found 

 to be phases in the life of the original cercomonad. The spo- 

 rules discharged by these encysted forms of this infusorian 

 were only visible with a sVth objective, and a magnifying pow- 

 er of 2500 diameters. "The development of these granules 

 was now watched with the greatest care. In six hours they 

 had increased to a decidedly perceptible degree, though still 

 far smaller than the minute and familiar Bacterium termo of 

 Cohn ; an hour or two later they began to reassume an oval 

 shape ; in nine hours from the first they had become rather 

 larger than B. termo, and had become flagellate, and begun 

 to move freely ; the bodies became vacuolate, and in some- 

 thing less than twelve hours the normal parent form was as- 

 sumed. This history was traced carefully and repeatedly, 

 and with unvarying results. The efflects of heat and desicca- 

 tion were also tried ; and it was found that, although drying 

 slowly upon a glass slide and exposure to a dry heat of 121 

 C. entirely destroyed all the adult forms, yet, after moisten- 

 ing again with distilled water, and watching the field for some 

 hours, growing points were in some instances discovered ex- 

 actly resembling an early stage of the developing sporules, 

 which points matured into the flagellate state. Further ex- 

 periments demonstrated that a heat, without dryness, of 66 

 C. destroys all the adult forms, while young monads appear 

 and develop in an infusion Avhich has been heated to 127 

 C, suggesting that the sporales are uninjured by a tempera- 

 ture which is destructive to the adult." Dr. Ward, in review- 

 inn- this article in the American Naturalist, observes "that 

 after this history whose importance, if verified by subse- 



