6 



preparations of Paris green to ascertain tlie effect of different 

 proportions upon the foliage. 



5. A biological collection has been started, consisting of a 

 series of inflated larvas, to aid in the determination of such insects 

 as may be sent to the station, and to serve as an object lesson to 

 every farmer and fruit grower visiting the insectary. Already 

 the work has considerably progressed, and a number of insects 

 are represented in all their stages, together with their injurious 

 effects upon the foliage of the trees on which they feed. 



The large and increasing correspondence of this department 

 testifies to its importance, and shows the keen interest felt by 

 those to whom the annual damage to their crops has become a 

 problem worthy of their most serious consideration. 



In the line of disseminating useful knowledge among the 

 people, an article was pul)lished in Bulletin No. 8 by Dr. Harold 

 C. Ernst of Boston on "How far maj' a coav be tuberculous 

 before her milk becomes dangerous as an article of food." Out 

 of one hundred and fourteen samples of milk taken from thirty-six 

 different cows, all of them presenting more or less distinct signs 

 of tuberculosis of the lungs or elsewhere, but none having marked 

 signs of disease of the udder of any kind, seventeen were found 

 in which the bacilli of tuberculosis were distinctly present, or the 

 actual vims ivas seen in 10 -(- per cent, of the samples examined. 

 As these seventeen samples of infectious milk came from ton 

 different cows, the percentage of detected infectiousness rose to 

 27.7 per cent. The milk was shown to be infectious by inocula- 

 tion experiments in seven out of fourteen of the cows from which 

 the milk came, — that is fifty per cent. These results are to a 

 certain extent preliminary, but they show — 



First. That the milk from cows affected with tuberculosis in 

 any part of the body may contain the virus of the disease. 



Second. That the virus is present whether there is disease of 

 the udder or not. 



Third. That there is no ground for the assertion that there 

 must be a lesion of the udder before the milk can contain the 

 infection of tuberculosis. 



Fourth. That, on the contrary, the bacilli of tuberculosis are 

 present and active in a very large proportion of cases in the milk 



