THE METHOD OF NEUHAUSS, ETC. 207 



.Neuhauss, Gronwald, and Oehlmann, calling to mind the in- 

 formation afforded by the fractional method of sterilisation, sought 

 to induce the hardy spores to germinate, in order that the end in 

 view might then be attained by moderate means. With this 

 object the milk is placed in bottles with loose-fitting stoppers, 

 which are then put into a specially constructed case, where they 

 are surrounded by steam and allowed to remain for half-an-hour 

 at a temperature of 8o-95 C. This so-called preliminary sterili- 

 sation is once repeated, with the result that the pathogenic and 

 the lactic acid bacteria are destroyed, and the milk is then left to 

 cool gradually, whereby it passes through the degrees of tempera- 

 ture favourable to the germination of the surviving hardy spores. 

 On the following day the samples are subjected (in the same bath) 

 to the so-called chief sterilisation at 102 C., and when this is 

 finished, the stoppers of the bottles are immediately and simul- 

 taneously tightened up by means of an arrangement manipulated 

 from the outside. The instructions given to adhere to a tempera- 

 ture of 102 C. prove that the germination of the spores is not 

 numerically complete, since, if this were the case, a maximum of 

 1 00 C. would suffice for the chief sterilisation, all the vegetative 

 forms quickly perishing at this temperature. If, however, spores 

 be still present at the commencement of the chief sterilising 

 process, the probability is by no means small that they will also 

 be able to withstand the short exposure to 102 C., and it may be 

 anticipated that even this method will not always accomplish its 

 object. As a matter of fact, reports are not wanting e.g. that of 

 M. BLEISCH (I.) to the effect that milk samples assumed to have 

 been sterilised by the method in question have been subsequently 

 discovered to be in a state of decomposition ; whilst Fliigge was 

 unable to confirm the favourable reports given by Petri and 

 Maassen, and PICTET and WEYL (L). 



In short, there is at the present time no practicable and 

 certain method for freeing milk (on a large scale) from germs 

 without at the same time seriously prejudicing its flavour and 

 nutritive value. Since, then, the annihilation of the hardy germs 

 in this case is so difficult, attention is now directed to their ex- 

 clusion from the milk ; the greatest care is therefore taken by 

 washing the udder, hands, and milk vessels to secure extreme 

 cleanliness in the preparation of " nursery milk " intended for 

 infant consumption. The so-called sterilisation then becomes a 

 much easier task, the milk, drawn with such precaution from the 

 cow, being very poor in the above-mentioned gas-forming bacteria. 

 As a ready means of detecting the presence of these organisms will 

 often be useful to the scientific adviser of a Dairy Association, the 

 fermentation flasks described by F. SCHAFFER (I.), TH. SMITH (I. 

 and II.), and others, are therefore recommended for the regular 

 examination of the milk supplied by the individual farmers as 

 regards its content of the pests under consideration. 



