38 On the Microscopical Examination [*^j°oumai"auTiSw''* 



forming a plentiful supply of cream. There was no appearance 

 of dotted matter or any fungoid growth when examined by powers 

 varying from 200 to 1500. The smallest oil globules exhibited 

 (as usual) great molecular activity. A bottle was filled with 

 some of this milk and securely corked, other portions of the milk 

 were placed in open cups, one cup was kept in a cabinet which 

 was closed during the day, the milk of the second cup was placed 

 in a closet the atmosphere of which I knew to be favourable to 

 the growth of fungi, the Mucor Mucedo being the most abundant 

 and of the same family as that mentioned as having been found in 

 cream by M. V. Essling. The milk in the bottle and that in the 

 cups was examined daily, precautions being taken to close the 

 bottle speedily after a portion was removed. On the third day 

 the milk in the open cups was sour to the smell, but no change 

 appeared visible under the microscope ; the upper portion of the 

 milk in the bottle had become very rich in oil globules by the 

 formation of cream. On the fourth day the casein had coagulated 

 in the milk in the open cups, and the flaky precipitate was visible 

 under the microscope; the pellicle surrounding the oil globules 

 now appeared to be very easily ruptured, and with the shghtest 

 pressure some of the globules could be joined together — sometimes 

 a number of globules which had been ranged in line by a current 

 would coalesce by a slight movement of the fluid, and form an 

 elongated mass. Fifth day, no appreciable alteration. Sixth day, 

 the milk which had been placed in the closet had patches of mould 

 visible on its surface ; a microscopical examination of this mould 

 showed it to be the Mucor Mucedo, such as I had frequently found 

 on fruit which had been left in this closet. The fungi appeared 

 on the surface only, no trace of it could be found in the milk taken 

 from various depths. The milk in the cup kept in the cabinet 

 exhibited no appearance of the Mucor Mucedo or any other vege- 

 table or animal organism ; it had become thickened into a pasty 

 mass with an intensely sour odour. These observations were con- 

 tinued for eleven days, and the only difierence observable was in 

 the oil globules — they began to lose their spherical form, as if the 

 investing pellicle had been weakened in parts and had become 

 expanded. 



These experiments were repeated with a second supply of milk 

 which Mr. Ejpping kindly supplied, and the results were alike in 

 both cases. The range of temperature during the experiments was 

 from 45° to 63° F. These experiments would lead me to believe 

 that vegetable organisms do not as a rule make their appearance 

 in pure unadulterated milk unless it is exposed for some time to 

 atmospheric influences ; most probably the spores are supplied by 

 the atmosphere. Further experiments are wanting to decide the 

 question. The microscopical examinations should be continued in 



