PROGRESS OF MICROSCOPICAL SCIENCE. 83 



any necessity for keeping them many months before examination, that 

 his results with organic infusions were obtained after a few days, and 

 that they were generally of a most unmistakable nature. To satisfy 

 my doubts on the subject he most kindly offered to repeat his experi- 

 ments relating to the production of living organisms in infusions of 

 hay and turnip in my presence. To this proposal (although I have 

 hitherto taken no part in the controversy relating to spontaneous 

 generation, and do not intend to take any) I gladly acceded, at the 

 same time engaging to publish the results without delay. Fifteen ex- 

 periments were made. They were in three series, the dates of which 

 were resjiectively, Dec. 14, L'ec. 20, and Dec. 27," of which we jmblish 

 only the third, referring our readers to ' Nature ' for the more full 

 results, which are of the highest interest. Dr. Sanderson says that 

 even after two series of experiments, which quite bore out Dr. Bas- 

 tian's conclusions, " it appeared to me desirable to ascertain whether 

 the condition of the internal surface of the glass vessels exercised any 

 influence on the result. I therefore heated two retorts to 250° C, 

 keeping them at that temperature for half an hour, and closed them 

 while hot in the blow-pipe flame. These Dr. Bastian charged by 

 breaking off their points under the surface of a neutral infusion of 

 turnip with cheese, freshly prepared for the purpose, without employ- 

 ing any of the rind. The retorts were boiled and sealed in the same 

 way as before, excepting that whereas one was boiled only five minutes 

 the other was boiled ten minutes. The specific gravity of the infusion 

 used was 1013. A third uncalcined retort was charged with some of 

 the same infusion containing no cheese. This was also boiled for ten 

 minutes. I was out of town from the 28th to the 30th, and therefore 

 did not examine the retorts until the 31st. Dr. Bastian informed me 

 that on the 28th, twenty-one hours after preparation, the liquids in 

 both the calcined retorts were distinctly turbid, the temperature of the 

 water-bath being 32° C. ; and that sixty-six hours after preparation, 

 whilst the turbidity was much more marked, each flask also contained 

 what appeared to be a ' pellicle,' which had formed and sunk. At 

 this period the fluid in the third flask had also become very decidedly 

 turbid, (a.) Neutral turnip infusion with cheese in calcined retort, boiled 

 ten minutes. — The retort having been tested in the way previously 

 described, was opened on the 31st. The liquid was very foetid, had an 

 acid reaction, and contained much scum. It was found to be full of 

 Bacteria, whilst Leptothrix existed in abundance in portions of the 

 scum, together with granules of various sizes which refracted light 

 strongly. (&.) The same boiled five minutes. — The state of the liquid 

 was the same as that just described, (c.) Neutral infusion without 

 cheese, boiled ten minutes ; retort not calcined. — In this liquid the rods 

 and filaments were much less numerous. In other respects its cha- 

 racters were the same. In each case before opening the retort it was 

 observed that a portion of its neck became drawn in when exposed to 

 the blow-pipe flame. As regards the results of the foregoing experi- 

 ments, it is unnecessary for me to say anything as to their bearing on 

 the question of heterogenesis. The subject has already been frequently 

 discussed in your columns. The accuracy of Dr. Bastian's statements 



